Do you mean bimbo by looks, or bimbo by the lack of brains?
For both, your best bet is either the gym, clubs, bars, or perhaps even wherever you're working on your gap year. Beautiful girls are everywhere.
If you just want a bimbo by looks, who has a personality as well and isn't shallow, you need to be interested in her personality. There isn't a specific type of guy they go for.
If you wants an airhead, then you need to look good, compliment them, buy them stuff... All that kind of superficial stuff. You need to be confident but remember they're used to people wanting them for their looks, so find a slightly different way of complimenting them.
But to be honest, that's just stereotypes. I know lots of bimbos, and they're lovely, and they tend to go for good looking rugby players, but that's only because they're gorgeous so they can get the best looking guys. One of my best friends is one of the most beautiful girls ever, and I would not classify the guys she goes for as good looking at all. Rather, their personalities are fabulous (on the whole), they're fun and funny. Another friend is also very beautiful, and her boyfriend is good looking, and they look good together, but he looks after her and treats her so well, as well as being a great guy.
So just be yourself but more confident, so you can approach the girls. Good luck.