"...how to go about Humanizing my midi tracks..." Play 'em with your digits on a keyboard or control surface, fix up bad timings in Piano Roll View, and if you gotta quantize, just don't do it to 100%.
"Humanizing" works best when some actual, imperfect Human input is actually behind the track in the first place. I'm not a drummer, but I can bang some drums out on my keyboard.
And it's not just the velocities which control the pulse of a beat, via louder and softer hits, it's also when when the notes come in, probably a bit more rushed in the chorus, maybe late a bit during a verse - it's the placement on a measure's grid also.
Randy B.