Got any alcohol at home? I always keep an eye on when the supermarkets are doing liquor offers and then get the rum and bourbon when it's reduced, like when the Jim Beam Black was on an offer in Tesco that made it even cheaper than the JB White!
Have two or three before you head out, then you're warmed up and relaxed, limit your consumption while you're out by making sure you stay out of rounds and get your own. Buy something like lime and soda (one of my fave thirst quenchers) but if anyone asks, say there's a vodka in there as well so you don't look like a sober wet blanket that doesn't have fun. Works out cheaper all round, still gets you merry enough to be chatty and stops you getting wasted.