Skateboarding help!!!!!!!?

im really starting to get frustrated. i've been skateboarding off and on since i was 11 and now im 15. i never know how to do tricks. but this past week ive been determinded to learn. i know hot to ollie and nollie. then i tried to kickflip..that was impossible. then i watched a couple videos on youtube about the plain "shuvit" it looked easy but i tried for ten minutes and ill i accompished was messing up my finger and getting a board in the back of my head. i started to catch on, i can land my left foot(front foot) but my right foot(back foot) was always behind the board(like when its sideways) what am i doing wrong!?!? is there anything i can do to help myself? what other tricks can i do except the ollie nollie and manual? and plz give me any other suggestions. i really wanna learn how to skateboard so dont be a jerk