you don't have to play fast to be good. in some Metallica solos they play some really slow, kind of epic, passages that are sometimes my favorite part of the solo.
at first though, i recommend getting the right beat that goes with the songs, the basic rhythm. then don't try to go crazy but do something that sounds like it belongs there and then stay on that train of thought. it can be slow, but if it sounds like part of the song then it will sound fairly good. then get something down that sounds good, it can be a rough skeleton of notes or something. THEN work on speed. my teacher recommended this to me and it has worked better than most of my other techniques. just try it at least.
so remember, make it work first, then crank it up a notch.
Thanks for listening to this small piece of me.