I can do blues solo's fine. Now I need to implement my soloing abilities into the minor key, and do them in the right key. Every time I try to write solo's over heavy riffs I can't do it. Any suggestions, things that sound cool, or anything?
Try writing stuff in just a normal Minor scale, not just penatonics. Use whammy if u have one, also use artificial or pinch harmonics as well. Learn modes, those should help some.
well the easiest way for you to learn how to play metal solos is to look up late 80's to early 90's metallica solos, you will notice the blues influence and how simple minor/pentatonic solo are. Try enter sandman, one, fade to black, and master of puppets (try the slower one first.)
Try using scales.
Major scales especially.
I am The Great Cornholio !
I need T.P. for my bunghole !
Tremelo picking, sweeps, tapping. The usual metal solo. I like to add alot of bends and pinch harmonics as well.
Just learn a bunch of solos and figure out which fingerings they use, aswell as what keys they are in and if you find certain notes to sound really good, find out what is the chord behind it and what interval the note is (for example the major seventh can sound awesome over the subdominant chord).

Metal guitar isn't generally that hard, it's just a matter of building speed. As far as theory goes it's very straight forward most of the time, compared to jazz, funk and other styles like that.