I beg to differ with those who reckon that it is ok to learn licks and use them in an impro. You can see that kind of premeditated stuff a mile away. It goes against the philosophy of improvising. Sure the chords mights be same, but a good improvisor will play a different kind of solo depending on their mood, the audience's mood, the other musicians, the venue, etc etc.

The way I have approached it is:

1. know what chord you are playing and what key you're in. Even if you don't read music, it's not hard to figure out what notes sound good with a D chord and what notes don't.

You'll start to notice things like if you're playing a 12 bar blues in C, an "Eb" will only fit the F7 chord (the second chord in the sequence).

2. Play with someone else. get them to play the chord sequence, and you just run scales up and down that fit with those chords. Once that's second nature, think of ways of varying those scales (rhythm, articulation, leaving some notes out.

3. Don't play anything you can't hear first! Hit and miss doesn't work. Singing scales and chords is a good way of finding out whether you know them as well as you think you do.

4. Eventually, you can start to play around with different kinds of sounds and modes.

That's my story anyway!

Good luck!