Aquascaping is a very important part and it always seems that it's never quite right. I've made quite a few changes to my own over time and have seen so many examples that I know what I want to do with my next tank. It might help to look in the Photography section at other people's full tank shots and you might get some ideas how to re-work your own rock to give it a natural feel.
It also helps to have more established coral vs adding smaller frags. It costs more, but if you desire your tank to have a fuller look quicker, you can get large rocks full of things like zoanthids, or acros with fuller branching, or larger brain corals, just as a few examples.
Just be patient, though, in time your tank will look more natural. It just takes some work.