There's a couple of things that you can do to ensure that your hummus comes out ultra super creamy and tasty. You can increase the fat, increase the cooking time, or increase the liquid (to an extent). All of the techniques leave you with a different kind of hummus at the end, but regardless, they're all tasty.
First and foremost is the option of increasing the amount of fat you put in. This can mean more olive oil or tahini than the recipe calls for. There's a couple of considerations to this method. For one thing, the tahini is going to thicken the hummus. It'll give it a mild bitter edge if you're too generous with how much you put in. Mind you, your chickpeas can take a lot! They can probably take much more than you think that they can, and still be extremely tasty. I've gotten away with (for about 1 lb of chickpeas, soaked, boiled, and drained) up to a half cup of tahini, and had it all come out very well! Just bear in mind that tahini is (1) expensive, and (2) mildly bitter. If you're already adding in bitter things, like bell peppers or walnuts (both of which can bring out bitter flavours if you're not careful), you want to ease on up with the tahini, and bump up the oil instead.
Unfortunately, adding extra oil to the mix means that you'll end up with a slightly more runny hummus. Again, this is OK, as long as you've got enough chickpeas and tahini to balance out. If you do end up (mistakenly) adding too much oil, throw in a handful of almonds to thicken things up. It'll take a little longer to grind it down until the hummus is smooth, but it's OK. You'll get there.
Finally, you can add a bit more water. Like the oil, you're still working with ingredients that will give you a more runny product, so please be careful when you add water.
I mentioned cooking time for a very good reason. For the best hummus ever, use dried beans, that you soak overnight in cold water, then drain the next morning, rinse well, then boil the beans until they're tender. You want the beans to cook until they're all the way tender. Don't stop until everything is cooked through. The problem with tinned beans is that they aren't built to break down. Something about the masses of salt that they're packed in makes it difficult for the beans to grind down to a smooth paste. They'll grind if you give them a long time in the food processor, but they'll take an awfully long time. It's not pleasant at all to have chunks of chickpeas left in your hummus.
Yes, it takes a lot longer, but the payoff is well worth it. Please soak your beans in cold water, then boil them the next day. Why does't pressure cooking or quick soaking (wherein you soak the beans for 1 hour in boiling water, drain, then boil over the stove) work as well? The beans don't get as thoroughly hydrated in quick cooking methods as you would when you're being slow and deliberate. That extra time that you spend in the soaking and cooking process will give you thoroughly hydrated beans, that are cooked all the way through to the middle, perfectly. No problems with stubborn beans that won't grind down properly.
I'll also note here that if you want to increase the lemon flavour in your hummus, please consider using the zest of the lemon, along with the juice. If you add too much lemon juice, you'll end up with a hummus that's closer to a dressing, than a creamy dip. The zest of the lemon will increase the lemony taste without increasing (too much) the acidity of the whole mix.
At the end of the day, I'd rather you were eating any hummus at all, because it really is a tasty and healthy treat. So even if it means you buy the tinned chickpeas, or use peanut butter or almond butter in place of tahini because your local store ran out of tahini and won't be in stock until the next week (this actually happened once), or you end up making it runny because you're using a blender (which you shouldn't be doing, but how am I going to stop you from doing so?), or you don't have any mechanical grinding tools, so you sit there and pound with a pestle and mortar, or a potato masher. However you get the stuff into you, go ahead and do it. I'll probably still enjoy it immensely, with either bread, sliced cucumbers, carrot sticks, sliced apples, or my greedy face.
2 cups dry chickpeas, soaked overnight, rinsed, and boiled until tender
3 - 6 cloves of garlic, peeled
1/4 cup olive oil
1/4 cup tahini
2 lemon, juiced and zested
2 TB cumin seeds, lightly toasted and crushed or ground in a pestle and mortar
Salt, to taste
1 cup water, in reserve
1 bunch parsley
3 TB olive oil, for topping
When your chickpeas are cooked to perfection, drain them well, and rinse them off in cold running water to cool them off completely. Add the garlic to the food processor, and give the blade a spin to chop up the garlic. Add the chickpeas, olive oil, tahini, lemon juice, and lemon zest. Let the food processor run until all the ingredients are combined thoroughly. Add water, 1 TB at a time, until desired creaminess is achieved.
Top with ground cumin, chopped parsley, and olive oil. Serve with bread, sliced vegetables, or a big spoon. :)