a word of advice, don't give the baseball style ejection signal. You're just asking for trouble with that. There is no prescribed signal for an ejection, so don't use one. I got in crap for saying "number 23, that's 5 you're gone" if i gave the baseball type signal i don't think i'd be on the court anymore.
Also, don't go out of your way to eject people. I feel i may have gone overboard (3 this season, althought all were deserving of what they got), but I never practise throwing anyone out, and you shouldn't either. Its the last resort.
After an ejection you inform the coach then the player, or just the coach if he's ejected, then you go to your disqualified player posistions and wait for the coach to leave, or for 30-seconds to replace the player.
Also, never have a big smile on your face when giving out the disqualifying foul.
