Chance plays more roll here than almost any other activity in runescape, let alone with such a risk. I do not recommend staking as it becomes addicting for many and is decided for the most part by "Chance".
If you want a handy hint, create an account with 99 attack, strength, defense, hp, and stake on it. level 130+ will have to 2-3x you b/c you are 113 combat.