Um... It would be really helpful to know if you are a member on Runescape or not... It would also be nice to know how much money you have/or want to spend on this. Smithing would probably be the most profitable out of the 3. Cooking can be cheap or expensive depending on how you do it. Range is pretty unprofitable depending on what you kill and what arrows and stuff you use. I think a fun way to get cooking level high is to do Gnome cooking if your a member, it's a minigame. If you want smithing fast, just buy ores off the GE and smelt them somewhere like lumbridge and bank them, then hammer them in varrock and sell them on the GE. Range sorry I don't really know whats best to kill. Try going to tip.it/runescape (just copy the thing into your address box) and they have good data about XP points and things to kill.