keep practising. you probably wont notice the change unless you record your self playing a lick. Then practice it for a few weeks then record it again. Play them both back and you cant honestly say there is no change. The key is to practice with everything.

You can get a teacher but you don't have to. Use sites like this one to find out stuff. If it doesn't work, then get a teacher. I have tried with teachers and they never tell me what I need to know.

With sweep picking, try sweeping without freting first. If you are ok with the picking bit, try just playing a lick as fast as you can using alternate. If you are also good with your fretting hand, combine the two, practice and whah laa!

I don't know if any of that actually helps. Hope it does