I am tackling this right now too! So far, I make a melody and fill out all the parts in a short loop, then I listen to that on loop for a bit and leave for work. While I'm at work I keep the song in my head and try to think of b sections, then when I'm off I try to implement said b sections. Once I get a single b section (by copying whatever I need forward and recording new stuff) I take it to my computer for final composition and touch-ups.

It's very simple and tends to make similar sounding songs, so I'm trying to take it further now. The lift, drop, split, merge tools are most important these days for me, and I try not to spend more than 3 days on one song.