"Mahayana" covers a lot of ground. The Wiki entry gives a basic overview, then you might want to research the myriad varieties individually. Major traditions of Mahāyāna Buddhism today include Zen/Chán, Pure Land, Tiantai, and Nichiren, as well as the Esoteric Buddhist traditions of Shingon and Tibetan Buddhism. For a Tibetan Mahayana viewpoint, try fpmt.org.
If you go to dharmawheel.net, contact member Huseng, who lives in Japan and has a solid Mahayana background, he can point you to the best info sources.