You are in the middle of the road and eager to continue.
The main objective of billiards is to pocket all the billiard balls before the opponent and after each shot to place the cue ball in perfect position for the next ball.
That is why it is important to make the break to get all the balls spread out, with the main and side spins, you will be able to pocket all the balls, more easily.
Defending is ideal for when your opponent has few balls left to win the game and you are not sure if you can pocket a ball.
You could also jump the ball or make a massé, however, this already belongs to the professional level.
To perfect your game practice with this exercise plan for the semi-professional level.
Below are the posts you should read and practice:
To continue to develop as a proffesional player, you should complete these exercises. Can you complete them all successfully?