One of the main things that lead to hypertrophy is progression which, as explained in the post about progressive overload, can be either in volume, intensity, density or frequency.
In order to improve in the gym you need to keep track of what you are doing by writing everything you do in the gym on a logbook or simply on your phone notes.
How does chasing the log work?
Chasing the log is the easiest way of progressing in the gym, first of all, after you complete defining what will be your training split (look at mine if you want), the exercises you want to do and in which rep range, you just keep improving in those certain rep ranges. Training after training you want to beat the log, beat your last performance and always improve either on reps or on weight (when you do more reps than your rep range).