When in 4wd, if you start to go sideways, give it more gas and it should pull itself straight again. The opposite is true if in 2wd. Play around in a parking lot with throttle/brakes to get a feeling for your vehicle. When in doubt, punch it out.

Also, duh snow tires...if youre running summers/all seasons, you'll have a bad time.

Weight, maybe. I run an 04 tacoma, and dont have any trouble without weight but it certainly wont hurt.