If you put more information and some code its a lot easier to help.
But here's a few things to watch for, I was making a composite sprite for a game too.
1. Make sure you have one main sprite you are adding the others too. Like a body sprite that arm sprite and leg sprite are added to that, not the layer. It will help you keep track of them in movements rotation etc automatically. as the parent body sprite moves they will too.
2. Watch the anchor points, where you place them will affect how you have to offset the arm and leg sprites inside of the body sprite.
3. If your sprite isn't symmetrical, mine wasn't, you may have to move the anchor point if you flipX to make it rotate properly where you would think it should be
Thats really all, just play around with the positioning and anchor points until it looks right.