Does Planet Fitness have free weights? If so, use those over machines for weight training. The plus side with free weights is that most people stick to the machines so there probably won't be too many people over there.
DON'T be afraid to ask for help! I actually found that a lot of people don't mind giving advice/helping out if you ask. I'm usually the only chick in the weight training area of my gym and the guys are very nice to me. Two of them even set up the squat rack for me when they were done...making sure to put it nice and low since they were at least a foot taller than me. Apparently they also knew what weight I usually started at and set it up that way too! I was so grateful!
Also nerdfitness should start paying me
, but I really do like their site. They have videos of exercises and show what exercises you can do:
http://www.nerdfitness.com/blog/top-posts/
Deadlifts and squats are great, deadlifts work your entire body, squats give you a booty.
If you want to gain STRENGTH then you should lift heavy for a few reps. It seems like it won't do much, but trust me, it's powerful