Cellulite is an odd thing.
You can be model-thin and have cellulite (I've seen it quite often.) Usually, it appears in people who have been naturally thin most of their lives, but who haven't done any strenuous sports-related activities throughout their lives, or in people who have been overweight, then lost quite a bit of weight. Is it essentially lumpy fat held just beneath the skin.
A great deal of it is genetic, though, and you can only do so much to stop it.
But here are a few things that can only help.
1. Drink LOTS of water. We're talking two liters a day. (But this is a good thing. You'll feel better.
2. Stay away from sodium. Always check sodium content in anything.
If you want, you can use a cellulite cream or "firming" lotion. I recommend Soap and Glory's cream ($12 at Target.)
And don't feel bad or anything. 98% of women have cellulite, including celebrities and models, who are often photoshopped.