My only advice, and something that i have found works well is that for each exercise you do, make sure u leave it knowing that u pushed urself right the way up. What i mean is that if you set out to do 3 sets of 8 reps, going up in weight each time, but still find that at the end u dont feel like you've done the job, then get back onto the bench and up the weight a little more and keep pushing it.

I know a gym instructor might say to do your third set, then stop, but its much better to leave feeling like you've realy pushed yourself, and is also a good way of judging how much extra weight you can stack on the next time you work that muscle group.

make sure you're upping the weights you lift gradually, say once a week add 2.5kgs to your bench, and make sure you are always doing this, because lifting the same weight week in week out does nothing for anyone!

Oh and one last thing... most days when i leave the gym, i can either barely walk (if im working legs), or i can barely strap myself into my car due to the ache in my arms... when this happens to you, you know ur working hard enough!

all the best mate, i know how u feel as im in the same boat as you. it does work, but keep at it, as its when u start working consistently that you notice the best gains.