First up thanks for providing the "Tip of the week" archive although it is a little sparse right now.
I have a tip to share for Tip #1.
Instead of using a new var to display percentiles, it is possible to escape the character so it is not interpreted. Simply use % as an escape character, so the code will become.
format["You have %1%% ammo remaining", _mypercentage];
ps sorry for digging up an old thread, but this resource is overlooked imho. Keep up the good work.
pps. That tip is no good please ignore. That does work elsewhere but not inside a format command it seems. Please forgive me.