Hey, mastering takes practice and experimentation!
It'll come with time, just keep working on it.
-Really nice update, this wrote out to be pretty nice! I really think that if you could, you should get someone to rap over your song about madness. If you can't find anyone, I'll take some time to do it before the deadline (if I can come-up with anything, it depends. I'm good at poetry, but it takes a little bit to start out).
-Overall, nice job. If you want some help with mixing, here's some tips...
-Listen for frequencies you don't like. When you find those in certain instruments, lower that frequency range by a little bit until the frequency is there, but out of the way. As for the reese (whatever you call it) and the bass drum, there's still some conflict in hearing both with precision. Honestly, I'd take the 1-2 Khz range of the bass drum and raise it 2 dB, or somewhere around. Experiment with that until you get a good bass sound between the bass drum and reese. PM if you need any more advice, gtg, dinner!
-ImperfectDisciple