The best thing to do is record yourself playing a basic 12 bar blues progression in A. So... A,D,and E. Make your recording extra long. Like as long as you can stand it. Or if you have the abiliy to loop the progression, do that. Another option is to find blues backing tracks in A. Play it back. While its playing, play your A minor pentatonic scale over it. Play it forward, backwards, stop halfway through and go the other direction, skip around. After a while you will start to notice that the root note, the A, which you will find at three diferent places in that scale, will sound perfect when played at the end of each progression. Or at the end of the twelveth bar. This is what people talk about when they say things like "resolve". When you find that... you can play anything you think sounds cool as long as you end each phrase or bar with that root note. This hold true for other keys as well. So if you hear a song in a different key, say E, you just play the E minor pentatonic scale over it and resolve on the E. Hope that helps and doesn't hinder.