DO PHYSICAL STUFF SLOWER THAN USUAL.
This does not mean that you have to walk around like your grandma (unless you're playing the part of your grandma), but it means that for a lot of physical motions, moving a little slower is better. There are certain instances this is not true, like hurrying to get off stage, but for the most part it's effective. Slowing down an action draws attention to it, so if it's not an action you want to draw attention to, don't slow it down.
Why does slow work?
Here's several reasons:
- Slower movements exaggerate what you're doing. For example, if you're swinging an axe, a slow swing draws attention to the action.
- Slower movements are safer for your partners. If you're in a fight scene with another improviser, chances are real-life punches (although effective for winning the fight) will ensure that partner never wants to be on stage with you again.
- Slower movements raise the odds that your partner will react correctly. Nothing is worse than a fake slap or a fake punch that takes place without the other person reacting. One reason this block often happens is due to the fact that it wasn't telegraphed correctly.
- Slower movements can be funnier. Of course, this can become a slow-motion gag that can be overdone, but slow movements set up an expectation in the audiences' minds, and that means those expectations can be disrupted... and bam, funny happens.