How do I meet other like minded females???

I'm predominantly straight but have always fancied women but never done anything about it, I am in late 20's now and would love to experiance being with a woman but have no idea how I would go about it or how I would no that they were that way inclined too. I can tell when men are gay (most of the time,) and I can tell when women are gay when they are very butch looking (I don't mean any offence) but those are not the girls I fancy, I like the pretty girls who dress like women also can anyone advise please