You can make a girl orgasm in a number of ways, the best is decided by what your girl is familiar with and what works best for her. The first and most obvious is the clitoral orgasm. This can be achieved by direct stimulation of the female clitoris, which can be found at the top of the labia major, or lips, where they meet. The clitoris can sometimes be hidden under a small hood of skin, so using your fingers to find it can help. Some women prefer direct stimulation, while others prefer indirect stimulation, such as rubbing the hood. The next form of orgasm is known popularly as the G-Spot orgasm. This can be achieved through stimulation of the G Spot, noteably found about 1/3 of the way into the vagina, on the top wall, or wall closest to her stomach. The G Spot is a centralized bunch of nerves that can cause orgasm when hit, or can make a woman feel like she needs to urinate. There are others but this is a short answer, for more information look on google or any health website about female orgasm.