One, if she tells you, that's easy. But try to pick up on little things, does she show pleasure by moaning? If she likes you enough to make out with you she will probably tell you what turns her on.
The easiest way is BDSM. If that's not what your into then make sure that a girl is bi so she's into girls. But your best bet is through BDSM. Trust me I know and I am girl.
ask her who she likes
Get to know her.
this is simple get to know this girl
If a guy look at the girl twice then it means she likes the girl
That means he girl likes you and answer that question by telling the girl something she likes to do. If you don't know what the girl likes to do then you're a goner
A girl who dominates someone in a bdsm type of way
Ask her.
ask her out
If no on likes you
I gess the same way you can tell if a normal girl likes you.
if she talks to you and touches you on the leg or something like that. then that means she likes you.