As I said, my preferred method is cunnilingus, but if the owner of your clitoris doesn't like that for some reason ("no, my dear, it's not germy and it does taste rather nice") then you'll have to use your fingers. I find that the best thing for clitori is a nice regular stroke, with regular exotic interludes. Basically it's the same thing as for penises - you don't want all sorts of unpredictable jerking around, and you don't want to feel like it's caught in a vise, and you don't want it to feel like it's attached to a reciprocating engine going at 5000 revs. Take it easy. If the owner of your clitoris wants more stimulation you'll notice her writhing around and pushing it at you. If she wants less then she'll draw away. If it's just right then she'll sit where she is and enjoy it. Pay attention to what she does. When it comes to pleasuring a woman, she says a lot more with her actions than with her words.

So, you've got a nice regular stroke going - say, seven strokes and then something exotic, and then another seven strokes and another something exotic. Of course the G spot is in the vagina, and you're going to have to know what's going on in there if you're going to find it and do something with it. Slowly insert a finger or two. Don't grab, because that can be rude and distracting.