To me, the trick to a good improv is knowing what will keep it from sounding like an improv. Haha. Here are some examples of what I mean:
-In my first minute or so of improvisation, I try to pick out a chunk of melodic material that I can repeat later.
-I think structurally. So after that first minute or so of improvisation, I intentionally try to do something that contrasts what proceeded to create more tension and interest.
-At some point, I quote earlier material. This makes so that the improvisation doesn't sound like a bunch of random, stitched-together ideas that jump all over the place. It makes it sound like a real composed piece with form and parts you might even be able to hum afterward.
Rather than think of this process as improv, it might be better to think of it as speed composing. The goal is to take the elements that make a memorable composition and consciously apply them to spontaneously created music. It also involves a good deal of thinking ahead while you are playing.
I also fall back on things I already know. For example, there are certain keys I'm very comfortable playing in, and there are certain chord progressions and left-hand accompaniment patterns I tend to fall back on. I've spent enough time consciously building a tool-set to draw from that I am able to focus on melody and not have to constantly start and stop. I'm getting better at doing this everyday. May next goal is to cut pauses and tempo fluctuations that come from my uncertainty about where to go next. I would like my improvisations to sound incredibly intentional.
So, that was probably a lot more info than you wanted, but hey, I enjoyed writing it! XD
Thank you so much for your review. :)