This is something that takes quite a while to do and the only way to really establish your own sound is to discover as many sounds as you possibly can. You need to make sure that you're consistently experimenting and playing with different synthesizers (or samples), whether it's hardware or software synths and experiment with different sounds. That is the only way you're going to find what you like and in time you develop a sound that is just your sound because no one is going to like exactly what you like!