Issac Guillory - what a FANTASTIC player he was (I'm not sure I've seen better) - and he described himself as a rhythm guitarist!

I'm not sure about RichM's post:
"To teach yourself to BEGIN to improvise, you need to start with melody."

It's vital to get the rhythm and timing right first, and that's probably best done by strumming chords. I've seen too many who've skipped this part in an effort to get to the melody and the much loved lead riffs. I know a few who have mastered quite a number of classic riffs, but are knackered when it comes to playing something they're not familiar with. As for improvisation, they'll never get there.

My advice - bottom up approach - from rhythm and chords - to fingerstyle - to melody notes within chords - to scale patterns - to lead guitar - and the Holy Grail

Issac Guillory (RIP) - the standard to strive for