Like other Force powers, the range of Mind Trick depends on how many Force points you invest in it (level 1, 2, or 3).
With level 1, you have to target a player in your crosshair, and it only works on that player.
With level 2 it works on all enemy players in your immediate area.
With level 3 it theoretically affects all enemy players, but at least one enemy player has to be targeted or in the area.
Players who are affected by your Mind Trick will have blue sparkles over their heads. Use of Force Seeing\Sight at any level will overcome Mind Trick. Also, attacking an enemy player turns off your Mind Trick.
Mind Trick can be useful in CTF for offense players (flag carriers). Turn off your lightsaber(s) or equip with a gun to make yourself less conspicuous. If you have level 2 or 3 Mind Trick, use it as you enter the enemy base to sneak up on the flag and steal it. However, as soon as you get the flag your Mind Trick wears off, and you can't use it while you are carrying the flag. You will need Force manna for Speed and Absorb anyway when you have the flag.
Set up a CTF game at home against bots using Play Solo Game. Practice using Mind Trick and homing rockets on the bots. Light side bots (Luke, Kyle, Jan, Jedi, etc.) might use Mind Trick on you. Have at least level 1 Force Seeing so you can overcome the bot's Mind Trick.
For more CTF tips, including tactics and information about strafe jumping (allows you to run really fast) go to my Education Page
http://www.chopshopservers.com/education)