Hi there. =]
Cellulite is basically trapped fat cells that are all stuck together,
which gives it that orange peel kinda look. It is mostly genetic.
You can get rid of cellulite though with a lot of work.
I used to have a lot of cellulite on my thighs and butt, too.
If you are not overweight then the most important thing to do is to weight train and gain lean muscle mass. Gaining lean muscle mass and getting toned will seriously decrease cellulite like mad.
The most basic things that you can do to tone your butt and outer thighs are squats, lunges, donkey kicks and leg raises. If you can, seriously consider getting some ankle weights (20 lb to start) or getting a gym membership so that you can use the weights there. The more weight that you use, the more cellulite you will reduce.
Also, change up your diet. No, not dieting to lose weight, but dieting to lose cellulite. Drink TONS of water, as much as you can. I drank about a gallon a day when I was working to get rid of my cellulite. Put some lemon or lime slices in there if you don't like the taste of plain water.
AVOID processed foods of all kinds, junk foods, candies, sodas and anything white (potatoes, white bread, white pastas). Eat lots of salads, vegetables (especially the kinds with lots of water in them, like cucumbers), some fruits (not to much, because it just turns to sugar),
and lean meats like chicken and turkey.
This is a really important tip. MAKE SURE to drink lots of green tea.
Get some without the calories. Green tea is amazing for reducing cellulite.
Try to drink 6 to 8 glasses a day for the full effect or consider taking a green tea supplement.
Another thing that helps is tanning. Darker skin tends to hide cellulite better than pale skin. Be careful if you go sun bathing though, 10 - 15 mins a day is enough to hide the cellulite without damaging your skin.
Also try investing in a lotion that will plump and tone the surface of your skin, hiding cellulite. Nivea's Good Bye Cellulite gel cream works really well and so do the patches and pills that come with it.
You can also get some sand or the Lush sandstone bar and scrub it on your butt and thighs where you have cellulite. Seriously, this is a Brazilian trick to get rid of cellulite. Coffee beans also work because of the caffine.
The last thing that I can suggest is maybe getting some body wraps or making your own at home.
http://www.wikihow.com/Do-a-Home-Body-Wrap
http://www.ehow.com/how_2107091_do-body-wrap-home.html
Body wraps and cellulite massage are also good for reducing cellulite.
I did all of this for about a month and my cellulite was seriously like almost gone, and I used to have a lot.
Good luck!