Well, a lot of people have asked me this, and I feel that the best answer is... sitting down for a long period of time and thinking, until you have the powers you want.  I know my views aren't popular, but Bearded Justice has fought and killed the lady known as popularity.  I've met many a young lad who complains that he cannot fly, and I day "Sit down, boy, and think of a way to fly!"  Most spit on me after this, and then I crush them into the ground. 
Although, that is a good way to gain powers, it's always good to eat someones soul and absorb their powers.  I've never done this as a soul does not sound tasty.  That doesn't mean you shouldn't!