Wall practice
Firstly, and most importantly, only practice what you've been taught! If you practice the wrong technique you'll build up muscle memory for the wrong thing! Generally if you've been playing 4 months I would practice ground strokes purely to "groove" the technique. So, stand sufficiently far away from the wall so the rebound doesn't come at you too quickly - hit it after the second bounce if necessary. Do NOT try and hit the ball too hard - remember, the objective is to groove the stroke not to get the rebound perfect! If the wall has a net painted then that is self explanatory but some have a line drawn a couple of feet or so above the "net" to indicate if the ball is being hit "long". Repeat, have a lesson, say the forehand drive, and then ask the pro this question. Good luck.