Here are some random points. Just scratching the surface but they help.
TEMPLATES!
Make good mixing templates to work in where you have preset tracks where everything is pre-routed and you don't have to think about it. It saves a ton of time. Account for more than you think will be needed. IE, be prepared to print separate VO, dialogue, music, and Sound FX stems at the drop of a hat.
Meters.
Get a good set of meters. Dorroughs with the loudness metering if you can. They are absolutely indispensable for post mixing. Try to calibrate your monitoring system with pink noise to a set level (I do 83 dB SPL) and keep it there. Helps keep a common perspective on everything.
Snapshot automation.
Learn it if you haven't. It's not all that hard when you get the hang of it. Once you get quick at it, you can move efficiently through various sections and not have to have a billion tracks to account for all the various audio. Also, snapshot automation requires you to arm every parameter of the plugin which means they're all easily accessible to dynamically automate. I do this all the time and adjust EQ parameters with the trim tool in the edit window just as I'll do volumes. Also, make presets as you go along. IE, if you're cutting back and forth between scenes with common audio properties, you can easily get back the setting you need.
Compression versus limiting.
Try to avoid the easy-to-fall-into-habit of compressing the crap out of everything. Compression on prodcution tracks can lead to some noise issues (noise with a pumping compressor is NOT good). Try and take care of leveling with volume automation. I do use limiters in order to keep the peaks in order though. These I try to make as transparent as possible. Also, mix dynamically if you can. If it's for broadcast, remember that there will most likely be broadcast compression on everything.
There are many more things obviously but there's some randomly chosen food for thought.