There are three ways that I use, depending on what part of my cycle I am on.
1) The romantic way. I imagine I am on a beach, or somewhere where the air is warm and I am being seduced gently and without a rush. I stroke myself lightly on my breasts and nipples, spending ages on each until I am on fire between my legs. Then I tease myself by stroking down my tummy and over my panties. I really work myself until I am begging my imaginary lover to take my panties off. Sometimes, I actually do take them off, other times I pull them to one side. By this time, I am usually so aroused that only a brief attention to my clit sends me over. The orgasm is usually gentle as waves washing up a beach.
2) At other times of the month, I need a little more daring to get me off. Sometimes, I go to school with no panties on and deliberately let guys get a quick flash up my skirt. Sometimes too, I even let the teachers get a look. It really turns me on to think they will have to go jerk off. At times like this, I will go to the bathroom at school. Sometimes I wait for it to be totally empty and then I make myself cum by finger fucking my g spot. Reaching orgasm this way is usually stronger in a physical sense than the first way. OTher times, I wait until I know there are other people in the bathroom. I imagine what they would do if they knew what I was doing. Sometimes, I even imagine a girl wanting to join me. (I haven't done anything with another girl in real life, but I know I want to.)
3) A couple days before my period, there is no other word for it, I feel like a complete whore. It is then that I indulge my most forbidden fantasies. I imagine being raped, or even having my dad fuck me. (My mom died three years ago and he hasn't had a girlfriend in all that time.) I go to my bedroom... (or his if he is away) and get a banana. I then role play with myself one of two scenarios. One is him seducing me, and the other is him being so horny he just has to fuck someone NOW) No matter which fantasy I use, I end up playing the 'innocent little virgin'. I even make myself imagine pain as I push the banana inside me. Then I fuck myself with it hard and fast. Just as I imagine he is cumming in me, I orgasm. THis orgasm though, unlike the other ways I do it is always really huge and savage. SOmetimes, I do this fully clothed with only my panties pulled over to one side. THe orgasms can be so hard that I pee my panties. Actually, I like this feeling too!!