Not sure if you play tennis in real life; but my below response; will be easier to understand if you do. If not, I tried to make it as clear as I could, I hope this helps.
The main thing to remember is to keep your angles in mind and realize your goal is not necessarily to pass them outright; but to create opportunities to pass them by creating space at the net where they cannot cover the passing shot.
I like to play the game the same way the teaching pros teach you to play in real life. Think about your passing shots as two or three set-up shots until you get the shot you can rip past them. This game just like tennis is all about your opponents pattern of play versus your own pattern of play. You should have a few patterns of play that you "go to" based on what your opponent just did. However, this game is similar to real tennis too because it also picks up on patterns you do; so even if you have a higher chance of losing the point by changing a winning strategy; it is beneficial to do so every few points the situation presents itself as to not become predictable. Remember,You are trying to create space and make it difficult for your opponent. This will not always happen on the first strike. You must have great footwork at the baseline for any of these strategies. You must also be able to react to the placement of your opponent as he's coming in to the net and the incoming ball's placement. As my last preface; lobbing is not recommended especially early in the rally against a skilled volleyer. They are ready to move back and knock of the smash. I remember reading in the past from Manutoo a long time ago; the CPU's get closer and closer to the net with each volley they hit in the rally. This makes each volley they hit more aggressive as they are attacking the ball and cutting it off. So if you are going to lob the opponent; it is best to do it after they have hit a few volley's in the ralley because they will have to move back much further than if you did the lob as soon as they come to net because you don't know what else to do. Here are a few suggestions i have for you.
When your opponent hits a ground stroke up-the-line, (Not cross-court) and runs in to net:
Your opponent approaches up the line in real life and in the game because it is the smarter play. by hitting a ground-stroke on the same side of the court he now has to run to the net on; he takes away almost all of your available passing angles. You as the person on the baseline; must work through a series of one, two or even three shots to regain the positional control. One way to get past them is If your right handed opponent hits a backhand up the line to your forehand (if you are right-handed player) hit your first shot as if they weren't even coming in right in front of you...just go hard straight up the line on the same side they are on- It's important this is struck so the ball is very close to the sideline and struck as hard as you can ('Fire 1 &2'). This will take away some of their angle and make them have to lunge even more to the right. This makes their volley less aggressive and puts them out of position. Remember, your goal is to create a bigger opening at the net to get the ball past them. Depending on the volleyers skill level and the accuracy and pace of your first shot; you may have to do same shot two times in a row, (I wouldn't recommend a third as they will usually pick off the volley at that point). Remember, when the opponent approaches up the line; it is a stronger position for them, so don't be discouraged if you lose some of the points. If hitting two up the line back at them for a few shots didn't work; try going for a soft cross court shot ('Fire 1' + 'up' and left or right). You are looking for the opportunity to hit your next shot in a bigger opening you created because they had to lunge to get the ball you just hit. The same thing works if they are a hitting an up-the-line forehand to your backhand (Both players are right handed in the example) side, just hit your first shot extremely hard and close to the sideline your opponent is coming in to the net on.
Returning serve: When your opponent hits a serve down the middle to either service box this is called serving "Down the 'T'". he's trying to take away your angles so he can get in to net and be able to knock off the volley- Using the same strategies for how to handle an up-the line approach would be best off of this type of serve.
When your opponent hits a ground stroke cross-court, (Not up-the-line) and runs in to net:
In real tennis and in the video game; this is a bad decision almost all of the time to come to the net after you hit a cross-court ground stroke. Remember, tennis is a game of angles; by hitting cross-court; they have allowed you many more angles to either pass them because you can go either up-the-line or cross-court and be in a very good position to win the point outright or gain a strong position to pass them on the second or third ball. When your opponent comes to the net right after they hit a cross court shot... smile, because they are in troubleIn this case; you can do almost anything you want and should choose the strongest shot based on your positioning. If you are already basically set where the ball is going to bounce; I would recommend going with a short cross-court angle as your best option. This almost always works. if you are having to run like a lunatic to get an aggressively struck cross-court shot; you aren't going to have as much directional control of the ball when you go to hit it- so your best option at that point is to hit as hard, ('Fire 1 & 2') of a shot as you can up the line. Also, after a long match and you need to add more variety; try doing a softer struck return short ('Fire 1' +holding 'up' and 'left' or 'right') to go soft and cross-court. This can mess up their timing big time and if they don't over hit the volley deep; they will certainly give you a soft volley you can rip by them. This is very effective.
Returning serve: When your opponent hits an angled serve out wide to either service box; he's trying to pull you off the court- Using the same strategies for how to handle a cross-court approach would be best off of this type of serve.
I would recommend using these strategies before hitting the lob. I only use the lob when I'm in a very defensive position or if they have hit 3-5 volley's and i cannot create enough space to hit a passing shot. Hope this helps!