#1
Ive been looking for lessons around the net, but they dont seem to have any. Do you just throw in licks in the same key for this? Or are there certain "rules" or stuff i must know?
#2
First, a lot of blues is played using all Dominant 7th chords. If you know theory that would also be called a "flat 7th", or "b7". Where the 7th is 2 semitones down from the root.

The "pentatonic minor" scale is often used to solo over MAJOR chords of the same. IE: Em pent, over the E7 chord. Yes that gives you TWO thirds together M & m, which creates a lot of the dismal feel.

You should probably Google these terms, "Blues scale, 12 bar blues, Blues chord progressions, and pentatonic scales. You could go straight to Wikipedia, as that's where the best textbook explanations will be. One subject tends to lead to another on Wiki, so that should keep you busy for a while.

Once you get those concepts down, you should be able to mimic and/or improvise to your hearts content. At least those will start you in the right direction

Adapted blues happens all over rock. I was floored when I found out that the Beatles, "Day Tripper", was almost straight 12 bar blues.
#3
like, Son House, Skip James, Muddy Waters delta blues? I can't say there are really rules, but listen to a lot of those old recordings and use a slide. Most of these artists played in open tunings as well.