You need to use slime finder! Search it on google. You just put in your seed, your location and then head to the nearest slime spawning area. Then dig a 16x16 area thats below level 16 in the area, and walk away. When you return, slime will most likely be there. If you neef help, feel free to message me on xbox. Gt: madinic21
http://www.minecraftforum.net/topic/1315731-slimes-101-xbox-edition-with-pic-guide-from-ar3-pics-from-your-progress-and-finished-farms-welcome-and-encouraged/
Read that
and add me if u need more help AgentX44Jobo
Slimes and Slime Farms 101