Sack Up and Track It!
One of the most underused muscle-building habits is keeping track of progress. If you want to build the most muscle in the shortest amount of time possible, you need to measure your success.
In the kitchen this means, yes, tracking your calories. I understand that it's inexact, a pain in the butt, and requires effort. Then again, so does anything worth having. If you can't get yourself to track your calories if you're struggling to build muscle, then maybe getting jacked isn't the right goal for you.
In the gym, track your workouts. Tracking strength numbers in big lifts like squats, deadlifts, and the bench press are important, but so is tracking all your lifts. Don't just chase one-rep maxes. Track your lifts in the traditional 6-12 hypertrophy rep range too. It's a great way to monitor your progress.
When you're building muscle, your one-rep max might not improve, but if you're adding weight to the bar on 6-12 rep sets, you can ensure you're getting the overload needed to build muscle.
Take Photos Too
Track your progress by taking photos every month or so. The scale and tape measure won't always cooperate. Photos provide another way to track results. Besides, you're more concerned with how you look, not how much you weigh on the scale, right?
Plus, progress pictures are a great opportunity to notice "lagging" muscle groups and formulate a plan to bring those muscle groups out more. Pinpointing weak areas of your physique and then emphasizing them in your training through supersets, drop sets, or finisher sets, is going to result in muscle growth.