I play a serve and volley game so I'll share what I try to do. I wouldn't suggest serve and volleying on every occasion at 13, unless you have a really good serve. Your height is a problem because it would be easier to get a lob past you and even when you get to the net you probably won't be able to cover it sufficiently. If you follow tennis, you are probably aware that serve and volley is not for everyone. Even among the world's best, only a minority are really proficient.That said here are some tips on what to do:
1) Don't try to do too much with your first volley. There are times when you get a really weak return and you can move in and win the point outright with the first volley, but usually you need to adopt a two-shot mentality. This would be a set up volley followed by an angled put away shot.
2) In order to execute a solid set-up volley, you need to move in, balance and go for depth and accuracy. Make a ready-hop (a kind of two-footed split-step) just as your opponent is getting ready to return your ball. Ideally you want to be as close to the net as possible, but it's much more important to be on balance, so don't worry if you're still in no-man's land. If you have a pretty fast serve you might only have time for 2 or 3 steps in before you have to make your ready-hop. A slower serve may allow you time for four or five steps. The main thing is to ready-hop in time and then aim deep.
3) Once you hit your set up volley don't stay in place ... move closer to the net (at the proper angle.) This will give you a stronger position.
4) This should probably have been first ... you have to place your serve very well and it has to have a good amount of pace if you want to serve and volley. Otherwise you will simply be in the middle of the court watching your opponent hit shots down the lines over and over again. You have to work on your serve and volleys non stop.
If your opponent starts to hit too many winners on your serve and volley game switch it up. Always keep them on their toes with something else ... for example instead of placing your serve as much as usual really blast one (a la Roddick style) in the middle of the service box. If you were only aiming for the T and out wide before that would catch your opponent off guard.
As far as chip and charging the same basic concept applies. Your "chip" has to be deep and accurate and put your opponent in a tough position and allow you time to get to the net. This will usually be achieved by using a slice shot.
Hope some of this helps. And if you need more (specific) tips let me know.
