1.Use wrist straps/grips on your last set of exercises like shrugs, deadlifts and rows to help you work certain muscles to failure when your forearms start to fatigue.
2. On most tricep exercises always remember to keep your elbows in close to your body and visualize your elbows only as hinge to contract the tricep. Keep your upper arms stationary.
3. A correct spotter for barbell exercises (ex. bench press), should only touch the bar on your last couple of reps when you start to reach failure. They should only need their fingers to apply just enough pressure to keep the bar moving upward.
4. A correct spotter for dumbbell exercises (ex.dumbbell shoulder press) should support their palms around the bottom of the elbows to support and apply just enough pressure to keep the weight moving upward.
5. When performing abdominal leg raises contract and control your abs to raise your legs, don't swing and use momentum to complete the exercise. Swinging your legs allows your hip flexors to take over the exercise.
"Free Weights or Machines?....Both is Best."