I've written out a long blog post recently about preparation although its mostly geared towards mixing. I'll try and keep this more geared towards tracking. sorry if its erratic topically, I'm just thinking and writing down as it comes to me.
I usually tell bands to record demos before we start, even if they're the most rough basic demos you can imagine. Not only does it give them a chance to hear their song back and make decisions on the arrangement, it also gives you an idea of elements you might want to improve and clues as to where you may need to focus more attention with them. usually references and talking about what their ideas and inspirations are is good to do to just so you both know what direction you're going in.
if they've done the demos in software you also have, you can load it in and possibly use the tempo if its well worked out, or use elastic audio/flex time to adjust theirs and listen back. Its also really useful to keep the guitars and vocals for the drummer to track to so they can play to the sound of the whole band. drums that play to the vocals are way better than ones that don't most of the time.
A lot of the time you'll need to record guide tracks so do guide guitar/bass/vocals/whatever is needed. don't just assume guide guitars are enough, sometimes it will be other things driving the song. also ALWAYS put markers in the project, it makes navigating so much easier.
make sure all the sounds you're capturing are what you want as soon as possible. that obviously means choosing the right drums/heads/tuning etc for drums, and the same attitude goes for every other instrument. have the attitude of making it sound like a final record as soon as possible and commit to sounds that you are sure are right. its best to do this as you go as the more big decisions you leave to the end, the harder time you'll have making sense of things. the best mixes are ones where you have to do very little so make decisions early and most importantly, get them right. you'll be rewarded more for making decisions than you will sitting on the fence the entire time.
often the bands equipment won't be right for the music they're performing, or it'll be in bad condition, or they may even not be using it to its full potential. how you deal and react with these things is what makes each producer unique and its impossible to predict until you find yourself in a new situation. just be creative, open minded and don't settle for anything than the absolute best you can do.
ALSO
always colour/label/picture your tracks. whatever you can to distinguish what's what. use folders, lay things out linearly, make it so any beginner could open it and understand it within a minute. the whole job is difficult with tons of decisions so the easier you make things for yourself, the more ambitious you can be with your work.
I'd recommend labelling things the way
these guys do. simplify projects down to individual sessions for what you're working on. have a separate project for guitars and do your guitar comps/edits etc here. in your master session, only have one playlist per track and make sure each track is the final, cleaned up, perfect version of the track you want. so many people dive into a mix before its ready to be mixed because mixing is fun and prep is boring.