In the options, you can adjust your hot keys to the grid pattern.
This will change the hotkeys so you don't have to remember them...
I would suggest to use Attack Move for long distance Attack commands and Patrol for short distance,
both keys will be next to each other which makes it more easier to choose between both.
Other than that, if you are into multi-player too, you might want to consider to learn the habit of attack moving your units through your opponent his army instead of in front.
If you are focus firing units you might want to consider to learn the habit to just (shift) right click on them instead so that when you are surrounding your opponent that you don't accidentally attack your own unit. Right clicking on your own unit cause your army to follow that unit, unless there's another next action in the queue to perform. So accidentally clicks on your own units have no effect when focus firing. Just make sure you don't click the ground instead, as they will walk instead of attack…
The grid pattern is Illustrated in the next picture: