#1
Hola! (i'm not mexican my the way)

I was wondering if anyone could give me some tips on playing fast. Like Marty Friedman, Herman Li, Darrel (dimebag) Abbot.

Also if anyone could show me some beginner exercises on sweep picking that would be very much helpful.
#2
You should go to the techniques forum. The mod Freepower has a very good sticky you should read.
Quote by Tyler Durden
It's only after we've lost everything that we're free to do anything.

Erowid
#4
This.

What I said about riffs goes for leads also. Teach yourself what you're trying play physically. Exagerate the fingering motions if you have to. Slow it down so you can practice it properly. Eventually it becomes as natural as brushing your teeth.

I read a great quote a little while ago. Something like "Amateurs pratice until they can play it right. Professionals practice until it can't go wrong".
#5
slow what ever your trying to learn way down, and then slowly, start moving up the speed.

Doing this to a metronome helps, you can start off ridiculously slow like at 60bpm, and then just work your way up 2 or 3bpm every time you can play the lick 5 times with out messing up. If you mess up at a higher BPM, start over from 60 and do it again.
#6
Another quote I heard and loved, and this is probably not the right wording, but it said something like "If you try to play sucky faster, you will only suck faster". Basically, slow it down like previously mentioned until you can play it perfect, then, and only then, speed it up.