You don't say what type of event and I will assume if you were referring to a bar event, you wouldn't need to ask this here.
If you are speaking of a private event... here are some basics. You need a speed rack with your well drinks.
From left to right they should be in the speed rack as follows:
Whiskey, scotch, vodka, gin, rum, tequila, and triple sec.
From there stock your calls liquors in the same order and keep all 'types' together. Exp:
From left to right..
Call whiskey...Jack Daniels, Jim Beam, Crown Royal etc.
Call scotch... Chivas, Dewars, Glenlivit etc.
Call vodka...Absolut, Ketel One, Grey Goose, etc.
Call gin...Tangueray, Bombay, Beefeater, etc.
Call rum...Bacardi light, Bacardi dark, Myers, etc.
Call tequila...Jose Cuervo, Patron, Jose 1800, etc.
Triple Sec... and orange flavored liquor used as a mixer.
Make sure to stock all your mixers, coke, 7-up sweet & sour, Roses Lime, etc. and cut fruit... lemons, limes, oranges, stock cherries & olives.
You will need plenty of glassware, bar naps, stir sticks, and ice.
That will get you started...