Dinner or bar: If there's a waiter, you order only for yourself and then immediately & confidently ask "should I pay now or later for that?". Don't ask your date "hey what are you having?" until after you order for yourself because women will use that as an excuse to say that they thought you were offering to pay for their drink since you ordered for her.
Only bar: Go up to the bartender and directly order your own drink, pay first, then turn and ask what she is having.
Dinner or bar: ask the waiter to split the bill when you order initially (don't ask permission from the girl and don't skip a beat in your conversation. This should be normal and she shouldn't be surprised that she should actually pay half).
Dinner or bar: say "hey, you know those chili fries look amazing! How about I buy first round of drinks and the chili fries are on you?".