Okay, despite what most are telling you, a Long Island is no stronger than a rum and coke, or any other highball for that matter. There's the same amount of alcohol in all of them with the exception of ones that contain liquor that's only 20% or so (amaretto is an example). People think that long islands are very strong because they contain 4 or 5 different kinds of booze, but the reality is it's about 1/4 oz of each when the bartender makes it (they usually have that stuff pre mixed and they use the hose dealy). Try a few things though. I usually pound 4 double long islands right when I get there to get started, then I'll slow down a little with some rye and cokes, and then when I'm drunk, I'll sip on a few gin and tonics.
Amaretto and cokes are very easy to drink, and aren't that strong.
You may want to try your luck with some shots too, if the night isn't going the way you want it to go. Tequila is probably the most popular straight up shot, and most people have a little thing with it. If you order one, they'll give you a slice of lemon and a salt shaker. What you do is lick the back of your hand, pour on some salt so that it sticks, quickly lick it off, down the shot, and start sucking on the lemon. They'll think you're a pro
If you're buying shots for girls, bazooka joes and china whites are creamy chick shots, while broken down golf carts are a little tangier, yet still easy.
If you want to show off a little, order a dr pepper (no, they won't give you the soda). The drink is 1/4 glass of beer mixed with 1/4 glass of coke, and a shot of amaretto. Drop the shot glass into the glass of beercoke (hehe), and then pound it back (it's easy).
If you have an asshole friend who you want to punish (great for birthdays hehe), order a prairie fire. It's a shot of 1/2 oz tequila, and 1/2 oz tabasco sauce. Nasty things them.
There are a couple of really showy drinks that you can do too, but they involve fire, and most clubs don't like that stuff. If you're interested in trying them out at parties and stuff, I can give you a few of those too.