I just got back to college so I'm starting to do weight training again for my muscles.
Oh nice! weightlifting can be a great form of exercise! 
Definitely, weight training is the best way to build muscle.
Do you switch between arm and leg days? 
When Im weight training I go between upper body muscles and lower body.
Do you use free weights or weight machines? 
Most of the time when I'm weight training I try to use the free weights but I use machines every so often.
Do you like to mix cardio in as well? 
Not really, I walk around campus so much that I'd rather stick to using the weights to build as much muscle as possible.
Nice it's always good to make sure you get cardio as well as weight training.