First of all, you should be following some kind of program whether you’re after fat loss or your goal is to gain lean muscle.
You need a guideline, something that has progressions and changes as you get stronger and in better shape.
A good program will change every 3-4 weeks and will last 12 or so weeks, at which point you should take a week or so off to give both your body and mind a much needed rest.
Why is change good?
If you are consistently doing the same routine, the same reps, sets, exercises, weight, every workout, your body will adapt to what you’re doing and your gains will stop, or plateau.
Now, don’t go nuts and just do something completely random and different each time you’re in the gym, eventually your body will get used to that as well. You need some structure, something that will guide you to your destination of getting a great body.
4 most important things to keep varied every 3-4 weeks in your workouts:
Reps: change your reps up every 3 to 4 weeks. example: weeks 1-3, 3 sets of 10. weeks 4-6, 3 sets + 1 drop set of half the weight with no set reps, lifting until failure.
Tempo: tempo is the speed at which you’re lifting the weight. weeks 1-3, tempo of 113 (1 sec on the contraction, 1 sec on the top of the lift, 3 seconds on the release or eccentric contraction). weeks 4-6, all out, no timing on the tempo, just lift as fast and as hard as possible.
Sets: weeks 1-3, 3 sets of 10 reps. weeks 4-6, 3 sets + 1 drop set – so it ends up being 4 sets.
Weight: gaining muscle, or burning fat is like anything in life, you want to improve at it. Lift heavier weights, add in drop sets at 50% of the weight to get a good burn out in there. Keep track of how much weight you’re lifting when you squat in week 1, then compare it to week 3, you should be trying to lift more come the 3rd week.
Have some scepticism when you’re choosing a program. There are good one’s out there, and there are crappy one’s as well.
Make sure they lay out a change in reps, sets, weight, and tempo every 3-4 weeks. It’ll keep you improving and get you that great body faster and more effectively.