TBH, I am surprised that nobody has mentioned instrumentation choice / palette yet. It does help if you think of the sounds that you want for the album as they will dictate quite a lot of the mix. I have a couple of stock synth pads, some standard approaches to drums, favoured way of recording and processing guitars, etc and this means that I know roughly how all songs will sound. Once I've used a combination on one album, I would try and change it around for another. Along with the changes in writing that always happen (or should imho), it helps keep things a little fresh.
Veni, Vidi, Aesculi
(I came, I saw, I conkered)