Going to echo the above, diet number 1, always top priority.
remember that change in the gym is real important too.
your body is one clever bastard..
when you arrive in the gym, your body knows whats coming.. its programmed to learn..
so then you start to smash it around in your usual way, and it doesnt want to rip up and grow, it wants to "survive" the workout...
so it will enter survival mode.. and try and slug it out..
so what you have to do is either hit it so hard it just cant survive and must grow to adapt, OR you hit it in a way you havent hit it before.. shock new growth!
lets say for example every monday is chest day... stop!!!
get in there on the monday and train legs for a change!
lets say every leg day is a heavy squat low rep day. stop!!! lower the weight, and ramp up the reps. 20 rep squats or something...
change is key.. different exercises you dont normally do.. those exercises you dont do because you hate them? do them!!!
also rep ranges..
your putting weight on there then hitting your 10 reps, or your 8 reps.. stop!!!! start doing a weird number such as hitting 11 or 9..
of course, dont stop if you can do another..
remember to really rip that muscle for new growth to occur, your last rep should be so dam hard, that your face is full of the pain, your arm or whatever it is is screaming, its unbearable..
i once spoke about the burn zone and growing reps to someone in the following way..
imagine your on a bus.. and the bus stops at various stops along the way with the very last stop the burn zone...which is your destination..
reps 1 and 2.. thats the bus moving.. reps 3 and 4. your still on the bus as its making its way towards the last stop.. reps 5 and 6, we still havent got to the burn zone yet.,.. but you get off!!!!!
you paid your bus fair to the driver, you sat on the bus, you almost got to the burn zone and then decide to get off!!! failure!!!
not only did you not reach your destination, you wasted your money and time as well..
its just like that with growing reps..
you pay all that money on diet and drugs and training to grow.. dont be getting off that bus before you get to those final grow reps. the burn zone..
stay on the bus till the end.. those last 2 or 3 reps, the holy grail of reps, the ONLY reps that lead to growth, reps so hard that your crying inside.. thats your burn zone, thats your failure reps, thats your growing reps.. dont just sit on the bus and waste your time heading in the direction of growth, make every set count and make every set a winner!
it doesnt matter whether you do a 5x5 rep range, or a 3x12 rep range, the same bus ride, the same ending..
but yeah, change is good.. keep it interesting, keep it varied, keep it different.