Q: where do i start to learn about mixing and mastering songs?
A: just listen to your song, and see if it sucks, and if it does, how the heck do you think you can change it. start by adjusting the volume, then if that doesn't work, listen to some other songs in a rage of panic and despair for a while, until you think of what else you might be able to try. eventually someone else will ask you how you do it so good, even though you still don't think you've figured it out yet