Learn all the notes on the bottom two strings. On top of that, I would at least understand how modes work so you can improvise and write progressions quickly(see: http://www.zentao.com/guitar/modes/#Introduction ). You will be able to transpose anything. I recently started writing my own stuff after improvising, or "jamming" with my favorite music online. Some of the greats learned guitar by playing with the radio.
Sounds reeeaaaaalllly melodramatic. I know this is metal and lyrics have been pretty weak in this genre overall(my opinion). But I would look outside for some inspiration. Read Leonard Cohen or any of the greats who write hours on this topic. Keep making music man. This is only opinion and I am not a songwriter myself blablablabla.
My unprofessional opinion: sounds like you are pouring on the macaroni and cheese there. The chorus doesn't really relate to the verses. If you want to express restlessness and unease, i would use a lot less adjectives and more verbs. Otherwise it's sounding contrived like something those karate-kicking hardcore bands would write. I know you didn't write this, but if you are the one singing the song, you should write the lyrics(they mean more that way). Only my opinion, I don't make a living as a musician or call myself a songwriter. Good luck and keep making music!
I own a Blue Yeti and it's excellent for this kind of stuff. Got mine at around $114 USD from Amazon. You can throw on the omnidirectional pattern (there's three capsules) and put it in the middle of the room. It's obviously not going to sound as good as tracking every instrument individually, but it will sound decent. If you plan on doing a demo I would play to a click track or something and record everything in isolation (best solution for how much you are willing to pay).