There's only one real way to get used to booze. Drink more of it. The more you drink it the more your body and brain gets used to it and the more you can drink in the future. Not that I recommend binge drinking or anything... I personally have about a glass of whisky a night. Maybe a double every now and then. And after about a year I started noticing that I wasn't getting tipsy any more from even a double. So yea...
Until then, pacing is important. In between drinks, eat something. Wheat products like bread and crackers work wonders. Water, for me at least, doesn't work. It helps with the hangover the next day but not with slowing my tipsyness and drunkness down.
And most importantly, probably, eat a heavy meal beforehand. lots of potatoes, rice, noodles, or other such things in it. That, and 'fatty stuff'. Bacon, butter, cheese, whole milk, etc.