So imagine someone's space when they're at the net and divide it into 9 squares: 3 columns forehand, body and backhand, and 3 rows high, middle and low. Then number those squares, 1 being their high forehand and 9 being their low backhand. Adjust if they're a leftie.
```
123
456
789
```
In *general*, aim for numbers 3, 5 (faster shot), 7, 8 and 9 (chiquita). However, during a match, you should assess how good their net game is at each square and adjust your aims. For example, square 6 is their middle backhand and many players practice this shot to death, so they could be quite good at it, but it's also one of those shots that a lot of players typically still suck at, so they miss a lot of them or their returns are of poor quality, giving you a chance to take over.
Other places you can aim at are any places not covered by these squares, so basically when they're out of position. If they're are perfectly in position, then make them move to create gaps, then aim for those gaps. For example, aim for their far 7 or 9, then aim between them to cause confusion, then aim for any gaps that appear.