The lights are on
Tip number one: Always, ALWAYS, level up.
As soon as you get the ability, and some gems, level up your Gravity meter, and Gravity Kick. This will always help you with the main quest and challenge missions.
Tip number two: finish the story BEFORE trophy hunting.
This game is quite long; so I suggest finishing the game before you go for the platinum. You will have more abilities and probably have an upgraded move to help with the challenge missions.
Tip number three: Try and try again.
If you get stuck on a challenge mission/story level, keep trying. If you are STILL having problems, find more gems and gold-medal some easier challenges to upgrade your abilities.
Tip number four: replay rift zones to collect all the gems.
Tip number five: do ALL the challenges.
This should be a no-brainer, considering the trophy for completing and golding al challenges.