Lots of people do it lots of different ways.
I think it depends on the booze -- liquor, wine?
Some people use RumRunners (google it).
Some have put it in mouthwash bottles but it seems like the cruiselines are onto this.
I think the keys are to not get greedy, hide it well in boots-shoes, put it in checked luggage -- not carry on, and don't put your eggs in one basket.
Sometimes some gets through but not the rest? It's a crap shoot.
The cruiselines tend to be more vigilant during Spring Break.
Lots of people are successful, though. Don't let the naysayers stop you. I won't.