With an Asperger child it is far better to anticipate the occurrence of a behavior and then plan for it. Many problem behaviors are repetitious, especially in the same situation. Even when they don't occur every time, they may still be frequent enough to warrant this approach. A rule of thumb is if a behavior repeats itself at least half of the time, you need to prepare for it. For example, if homework, bedtime, or dinnertime have been frequent problems in the past, chances are very good they will continue to be so in the future.
Future vision is the ability of an individual to know what is going to happen in an upcoming situation because of its constant reoccurrence. When you know what is going to happen you can prepare your child for the event prior to its occurrence by discussing what usually occurs and what needs to occur. For example, going out to dinner is often a problem time. So talk with your child about what normally happens, how he acts, how you do, and then follow that up with a discussion and see if you can get a firm commitment from your child that he is going to follow these new behaviors. If he responds in a positive way, you have increased the likelihood that things will go better when you go out for dinner.
If you happen to miss the opportunity to prevent a problem, there is often a small "window of opportunity" in which you can still salvage the situation. In the example above, suppose you have forgotten to say something before you left for dinner. As events begin to unravel, you have a very brief period of time sometimes only a minute or two before you'll be in a messy situation. Seize this opportunity. It may be the last best one in that situation.