Who We Are has different guidelines for ability creation than most sites, so I'm going to be as explicit as I can here.
You powers are based on your character's personality. The energy of the Infinity Tablets (see the plot) amplifies qualities that were already inside a person. This means that there has to be justification for your character's race and powers in their biography.
The way to make a character is personality first. Once you have their personality, decide what aspect of it sticks out, and then slot them into a race based on that. Once you've done that, then you can start thinking about the specific abilities to give them. Be as creative as you want; as long as you can reconcile it with their personality, any power is fair game. In fact, unique and interesting abilities appease the admin, and he's much more likely to let you get away with something a wee bit more powerful if it's creative enough.
The connections you can draw between personality and power don't have to be straightforward, as long as they are apparent in your profile. Some personality traits lend themselves to multiple powers and even multiple races. For example, someone who is known for his extremely hot temper could easily have fire-based powers (an Energist), but could also easily be full of wrath, and hence more inclined to a Shifter. If you want ideas or help making what you want work out, PM the admin. He'll be happy to help.