1) Make sure to only use free weights. Machines isolate muscles while free weights force more of your body to engage to stabilise the movement.
2) Intensity is the keyword here. You get stronger by increasing the intensity of a movement. Now usually, you do that by piling on the weight, but you can also do that through a couple of other methods:
- engage your antagonists: All the muscles in our body come in pairs that oppose each other. So if you are doing bicep curls, for example, tense up the tricep as much as you can to oppose the action. You will be sweating buckets.
- pre-tension: Before you begin the movement, tense up the muscle you are going to work on, and then keep the tension high throughout the movement.
- radiation: Make a fist, and notice how the muscles in your forearms tense up as well. Now make a stronger fist, and you notice that now, your bicep and tricep are also engaging to support the action. Even tighter, and now you are engaging your shoulders, even your chest and back muscles. Try and apply that same principle to every movement you do, starting with how you grip the weight - crush that bar into dust.
For more details on this sorta stuff, I recommend you look at the books of Pavel Tsatsouline, the Iron Russian (Corny, but he's good) He specialises in helping martial artists and power athletes train.
Hope it helps honey.
~Simone.