Starting at the intermediate level players begin to realize that they can actually return put-away shots, whether it's by blocking, countering, fishing, lobbing, or chopping. There's no magically fast reflexes needed, just a little knowledge and technique. Here are some tips on how to put pressure on your opponent by returning their put-aways - and remember, they are often off balance and rushed if you return them, and will often miss the next shot.
1) Depth. Probably the most important part of returning a put-away shot takes place with your previous shot. If that shot landed short on the table, then you both have little time to react to the opponent's shot and you have more ground to cover since you've given the opponent a wide angle. So if you are going to make a weak shot that the opponent is going to try to put away, keep the weak shot deep on the table.
2) Away from Table. You need time to react to the opponent's put-away, so step off the table to give yourself time. Even blockers may have to block from a step back.
3) Ready Stance. You need to be in a proper ready stance that allows you to quickly move in either direction. This means feet at least slightly wide, weight on balls of feet, knees bent, leaning forward slightly from the waist, racket in front of you pointing at the opponent.
4) Watch and Study Opponent. You can read the direction of a put-away shot before your opponent hits the ball. First, watch his shoulders. They usually line up in the direction of a forehand shot. Second, watch the direction of the forward swing, which should also tell you the direction. Third, be aware of the opponent's position. If he's way around his backhand corner but facing toward your backhand, it might be difficult for him to go down the line, and so he'll likely go crosscourt. And fourth, be aware of your opponent's habits. Many players will go the same way over and over, often crosscourt, so if necessary you can anticipate that direction.
5) Step to Ball. Amateurs react to a hard-hit ball by reaching; top players react by stepping, and reaching only when necessary. Many players believe they just don't have time to step to the ball, but that's because they have developed the habit of reaching instead of the habit of stepping. Learn both; you can cover more ground more quickly if you both step and reach.
6) Placement. The goal isn't just to return the put-away shot; the goal is to win the point. If you can return a put-away shot, you can also place it. So focus not only on getting the ball back but on placement and depth. Depth is a must or the opponent will just cream the ball again, and likely won't miss. Keep it deep, and he'll both make more mistakes and you'll have a better chance of continuing the rally. If you move the ball side to side you are more likely to force a mistake.
7) Practice. Of course you can't return a put-away shot in a game if you don't practice it. Can you do anything at a relatively high level in a game without practicing it first? So find ways to practice returning put-aways. It'll not only make you a better practice, it's fun!
8) Confidence. It's not enough to just go through the motions; you have to believe you can do it. If you are confident you can return a shot you won't hesitate to go for the return, and you'll have a much better chance of making the return. Just watch your opponent and the ball and let your subconscious react. With practice, it'll become easier than you'd think. Decide what your primary way of returning a put-away shot will be (blocking, countering, fishing, lobbing, or chopping) and become a master of that shot.