You will get more out of using free weights then machines since it takes more stability to keep the weights in proper position.
I have found squats, lunges, and running to have strengthen my legs. To maximize your time in the gym you can try combo exercises. Example- Grab two weights (one in each hand same weight) that feels a bit easy to lift but not too light. Stand in a lunge position (one leg forward then the other), holding the weights at about your hips and drawing in your stomach, lunge down, come back up, curl the weights and in the same movement raise the weights up into a standing press, bring the weights back down into reverse movements and repeat. Try 10 on each leg.
If you look online you can find good information on routines that can help strengthen the entire body :) If doing strength training for the day start out with about 5 minutes of cardio to get the blood moving
It's not the will to win, but the will to prepare to win that makes the difference.
- Paul "Bear" Bryant (Former college football coach)