1. You lift hard for a week then skip the gym for the next three.
Consistency is the key, and we're not talking about just a few weeks here. You know those monstrously muscular dudes you look up to? It probably took them years of dedication to develop that kind of physique.
2. You follow around the biggest, most roided out guy in the gym, doing whatever he does and hoping he doesn’t notice.
You’re not him, and you probably aren’t on the same juice he is. Unless you are, in which case, go right ahead and follow him around. But know that at some point, he will probably notice. So you might as well just introduce yourself and ask for help. Hopefully, he's not as mean as he looks.
3. You train with a body part split, hitting each muscle only once a week.
Frequency is essential for growth. Hit each muscle group a minimum of two times a week, ideally training your entire body every session.
4. You look like the Hunchback of Notre Dame when you attempt to lift.
When you deadlift with a round back, you’re putting a ton of stress on passive restraints, not your actual muscles. The only thing getting bigger here is your impending emergency room bill.
5. You don’t even deadlift -- or do any compound lifts for that matter.
Multi-joint exercises work the most muscle. Save the isolation exercises for after you squat, deadlift, bench, overhead press, row, and pull-up.
6. You spend half your workout doing “abs.”
You'll definitely feel the burn from lying on the ground and repping out hundreds of crunches, but it’s not lifting. In order to look like you lift, you actually have to lift something, even if it’s just your own bodyweight.
7. You use the range of motion of a Tyrannosaurs rex.
It doesn’t matter how much weight you put on the bar if you don’t move it more than a few inches. Purposeful partial reps are one thing; only ever doing quarter-squats is not. Stick to full range of motion the majority of the time.
8. You don’t eat enough.
In order to gain muscle mass, you have to take in more calories than you expend. It's simple thermodynamics, gang! That doesn’t mean you need to gorge yourself every meal. A couple hundred calories above maintenance on workout days will do the trick.
9. You consider jogging to be a lower body workout.
Refer to #6: You actually have to lift in order to look like you lift. Low-intensity cardio has a purpose, but it doesn't stand in for good old squats and deadlifts.
10. You don’t rest enough.
Training hard eight times a week may sound hardcore, but it's really just stupid. You have to give your body a chance to adapt. This means planned recovery days, some sort of periodization scheme, and — perhaps most importantly — plenty of sleep!