Most RTS have a "feature" (more like a bug to my programmer's opinion) called "Animation cancel".
Basically when you have a unit that does a particular task, like attacking, it has a pre-programmed animation. The zealots will slash with both arms, or the stalker will position itself and then shoot its lasers. Now what is important to understand is the order where these things happen
- Player issues a command
- Unit makes its animation
- Effect is done (Damage is dealt)
- Order cooldown enters in effect. Usually there is a post damage animation, like the marines will lower their guns or such
The idea behind animation cancel is that by skipping step 4, you can attack faster than what would normally be allowed. It can also be used to move and fire nearly at the same time.
This is actually simple to do. After you've attacked and animation 1 is underway, right click fast to move. As soon as your stalkers will have started moving, attack or attack move again. This will allow you to skip a (very small) part of the cooldown. So the following steps are used
- Stalkers will shoot lasers
- As soon as the lasers are shot, click like mad to move in any direction
- As soon as the stalkers will have moved a tiny bit, go back to step 1
Finally I'm pretty sure that stalkers are faster than zealots so this shouldn't be too difficult