Variations
While these tactics will give you about 80% of your game plan, you will still need some variations to prevent your opponent getting into a rhythm. Here are some change-up strategies that I would suggest to keep him on his toes and off-balance.Drop Shot
A good drop shot can be very effective, especially as your opponent is not so good at coming in and out from the table. Look for opportunities when he has his weight leaning back - he will find it very difficult to get up to the table and make a good shot - he will probably have to lunge to get your drop shot back - and you can then use a strong attack while he is caught with his weight leaning too far forward.
Don't overuse it though - his return needs to be fairly short to allow you to get a good drop shot - unless you have a great drop shot or he is very slow to get in! Drop shotting from deep returns is low-percentage for most players - so avoid it.
Attack to the Backhand
As your opponent works out that you are concentrating on his forehand, he will start to try to cover more of his forehand side with his long-pimpled backhand. This is the time to switch to an attack wide to the backhand side, which hopefully should go right past him, and which will then force him to come back to his left in future rallies to avoid being passed down the line again.
Run Around the Backhand
When your opponent pushes to your backhand with the smooth rubber, every so often run around and hit a forehand loop, preferably to his crossover point, but wide to the backhand can work too. Go for a winner here, since you don't want to have to play the next ball off the long pimples if you can avoid it. Since you are going to the long pimples, the resulting block or chop should be slower, giving you more time to recover and hit the next ball if it does come back, which is important given that you only have average footwork.
Another option is to take a chance and run around the push and go straight down the line with real power. You are basically trying to get a quick point through surprise - if your opponent manages to block the ball, it will be with his smooth rubber and the normal angle will be crosscourt, so most likely you won't get to the return with your current footwork. It's a good strategy to try on a pressure point - a bit of a gamble but with the odds in your favor if you haven't been using it too much.
Attack From the Long Pimples
Try this strategy at the beginning of the match, just to see whether it is your day with reading the long pimples (remember, you are normally a bit hit or miss against the long pips). When you are in a push rally, push a no spin ball to the long pimples, which should come back pretty much with no spin or just a faint bit of topspin, and then try out your attack. Give it a go three or four times just to see how you are hitting them today. If your attacks are going on - great! You now have another option to use, and can start looking to push no spin balls to his long pimples, and attacking to his forehand from his return down the line - the wider to his forehand the better. If he hits his return to your backhand or down the middle, you can either push it back or take a chance and run around it as you prefer.
If you miss the first few attacks from his long pimples, shelve it for the day, and maybe try it once a game just for the variety. If you start to hit them on again, use it more often.
Let Your Opponent Attack You
Don't be afraid to let your opponent attack you every so often. After all, as an attacker you should be used to playing other players who attack you back! The key here is to choose in advance when you will allow him to make his attack, and don't let him attack well, so that you have an easy counter-attack.
Since your opponent won't attack any 50/50 balls, you need to tempt him with a return that looks easy but isn't. High pushes with varied spin, or slow high topspins, both to the deep middle backhand will look easy to hit, but they will force him to run around to his backhand (since he doesn't hit with that side), opening up his forehand side to your prepared counter-attack. They can also be difficult to attack for a defender who is used to attacking with his forehand from the forehand side, due to the different footwork involved.
