The food you get in a restaurant tastes the way it is for various reasons. One is the seasoning. Another is the collaboration. Another is the presentation. I'll get into each, so that you all can dish out a very festive meal when the time comes for it.
I cannot emphasize enough the importance of seasoning your food. I'm not even talking about herbs, spices, or anything fancy or esoteric. Just plain salt will ensure that your food tastes right. When it comes to seasoning starchy foods (rice, pasta, potatoes, etc), season as they cook, so that they have a chance to get the salt into there. If it's vegetables and the like, feel free to season once it's done cooking, so that you don't end up with over-salted vegetables. In cases of soups and stews (and especially daal), I tend to wait until the last minute to salt my food, because I don't want to have to account for evaporation and the like throwing off the amount of salt that I've added. Unless you have a recipe that specifies an amount, wait until the end, add a bit of salt, see if that improves things, and keep adding in small amounts until you get to where you're comfortable.
Some people argue that it's better to leave the food unsalted, so that the folk who like more can add more, and those who don't like as much can leave it out. This is good in theory. Unfortunately, in practise, it makes it so that you have the person who's eating leaving things alone to be polite, and quietly choking it down, even though it's bland as hell. I don't know where the stigma behind salting at the table comes from, but it runs pretty strong. Even at home, when my husband and I are having something quick, under-salting is a problem. Rather than adding enough salt to his liking in a dish that's unsalted (which happens by mistake from time to time), he'll flat out avoid it all together until I add some salt to the dish. Then, once he's seen that it does taste good, he's able to adjust up if he wants more than that.
In other words, you need some salt to get the party started, so that people don't avoid the dish all together.
In a good kitchen, there is no space for ego. Yes, there is one person in charge of the whole meal. So what? Everyone can teach you something. No matter how new someone is to cooking, that person still has her/his own opinions on what tastes good. That's why, when we're in a restaurant kitchen, we don't work in a vacuum. Everyone, from the dish person, to the waitstaff, to the line cooks, and the management tastes a new dish. We all give feedback (more salt, too spicy, not enough pepper, not creamy enough, needs more fat, is a bit greasy, odd texture, needs crunch) based on what we like. The person making the dish will incorporate that into the recipe to improve it. It's why a restaurant is able to turn out delicious recipe after delicious recipe.
We're obsessed with food. We talk about it all the time. When we find a new method, or an interesting recipe, the first thing we do is share it with each other. Bossman likes to read magazines and newspapers. He's especially a fan of the food columns in the New York Times, because they provide such a varied set of people with different inspirations. Even if the recipe isn't vegan, we can easily make it vegan. I like YouTube. I like it a lot. My mother and I will watch those cooking channels made by individuals. They've frequently got recipes just as good (if not better) than cookery books. Because they're working in kitchens that are similar to mine (actually, their kitchens are much larger than mine; my home kitchen is tiny), with similar tools, and similar concerns, they'll often come up with neat ideas to do the same thing that I've done a million times. I also enjoy online cooking forums. They'll frequently have other food nerds around, who enjoy eating and cooking. It's a wonderful thing to bounce recipe ideas off a group of people you trust, who will then come back with suggestions to tweak or improve what you've started with.
The point is that even if you don't work in a restaurant kitchen, with multiple brains around you, you can still reach out to others to get that same feedback we get. If you have anyone at all who's interested in food who's helping you to cook, let them taste everything. This is especially good if you have children underfoot. They love to help out (if they're like the children I've met), and are usually thrilled to be asked their opinion on something that you're cooking for a large group. A simple "Hey, can you please check my food for salt", will often be greeted with enthusiasm.
More so than the recipe development or tasting collaboration, a restaurant kitchen has work collaboration. Rarely will I have to make a recipe all by myself, from start to finish, without someone helping me out. Whether it's our amazing dish person, who swoops in and clears off dirty dishes to be cleaned immediately, or my fabulous coworkers, who offer to knock out vegetable chopping tasks, it's a lot more enjoyable to cook when you have help.
Nobody who is helping you is doing an unimportant job. My job would be impossible without someone to help me clean up. I worry about the dish person if he's a little late, because it will bring our production to a screeching halt if we don't have someone who's around to enthusiastically keep the place sparkling clean. Similarly, at home, I really like it when there's someone who's there to keep the dishes from piling up (and pile up they do!), so that at the end of the night, it's a question of just washing the serving plates and the eating plates, rather than the myriad preparation bowls and cookware. If your guests offer to help you clear up, take them up on the offer! If someone offers to help you out in the kitchen, have them do something that will let you concentrate on other tasks that only you can do.
There are times when my boss and I will head into the kitchen together to make something. It's not that the other cooks don't know how to do the tasks I'm doing. It's not even necessarily that they're so busy that they can't lend a hand. Sometimes, the two of us just need some time by ourselves, to talk and get work done at the same time. This happens at home too. When I cook with someone, we tend to talk about things that won't come up in regular conversation. There's a bond that we form over that food preparation that isn't quite the same as any other bond. Something about working together to reach a specific goal just makes that task fun, and meaningful at the same time.
Either way, the point is that if you can get (or recruit) help when you're cooking, by all means, take it.
Finally, there is the point that in a restaurant kitchen, common tasks will be done en masse. If we need to have peeled onions (which we do), we'll peel a 50 pound bag at once, so that the next person going in to reach for onions has some already peeled. If we need chopped ginger and garlic, we'll make 5 pounds at once, so that we'll have chopped ginger or garlic ready and waiting (although here that 5 pounds will only last a day or two tops, you can keep about a couple of heads of chopped garlic, and a palm-sized knob of chopped ginger around for about five days in the fridge). We keep bunches of parsley already chopped, and waiting to go into things as a garnish. In other words, we do the boring bits during the slow times, so that when the crazy times hit, we aren't wasting needless steps on preparing the starting ingredients. It takes me just a few seconds to roughly chop an onion. Once that's done, and I already have chopped garlic and ginger, along with my salt, oil, and a pot, I can get pretty close to any recipe started with the sauteeing or sweating of the onions within a minute or so of prep time (especially since the onions are already peeled). Once those onions go into the pot, it's just a few more seconds of gathering additional ingredients to make my food.
In other words, if you're about to embark on a major holiday spread, have those recipe starters (onions, garlic, chopped celery and carrots, chopped ginger) ready and waiting for you. If you are doing the prep work just a day or two before, feel free to chop the onions, and put them into a zip top bag. Then chop your root vegetables, and soak them in cold water. That way, when the day of arrives, you just have assembly work to do.
Finally, at a restaurant, we pay attention to how your food looks. This isn't just about plating things beautifully. It's about the entire dish itself. For example, if you make a stew or soup, and everything is brown and dark coloured, we'll frequently put something in there to break up that colour monotony. If you have millet, sweet corn, and squash, you're going to end up with something that looks monochromatic. In cases like the millet example, I'll throw some kind of green vegetable into the mix (maybe some broccoli, or chopped kale). If I'm making something of any green, brown, or yellow, I'll generally throw some red in there. There's a reason that so many restaurants will have red peppers in the food: it really pops with red without bleeding onto anything else. When you have beets, or tomatoes, it tends to leak onto other foods. When you have bell peppers, however, you have a sharp blast of colour that's self-contained.
There are many things you can do at home to make your food look and taste as good as the food you get outside. For sure, some restaurants that you go to will bump up the fat content of any meal that they serve you. This is especially true of fast food or chain restaurants. There are diners where they bring in pre-made, mass-produced frozen meals, which they just heat up to serve you. However, people still cheerfully eat them. This is not the sort of "nicer tasting at restaurants" food I'm talking about. I'm talking about those places that make healthy, delicious food, consistently. That's why I didn't just tell you to throw fat at your cooking until it yields.
If you don't have local friends or family who are interested in food, find people online. They exist! If your children are uninterested in helping you cook, at the very least get them into the kitchen with you to taste the food as you cook, so that they get an idea of how a recipe can be tweaked to make it work for you. Especially in the case of massive parties and festivals, have multiple people give you feedback on your dish, until it's exactly where you'd like it to be.
And finally, know that even when you make mistakes, you learn something new. That in itself is a valuable enough reason to get into the kitchen and get to cooking.