Recently after having my first baby I was upset about how I looked. I have always been skinny and I didn't feel like my regular self. So I paid to have a membership with the Y.M.C.A. and got with a personal trainer. I would like to pass onto what has been given to me. To burn fat you want to do cardio. Your target heart rate should about 150 or above to get better results. My trainer said that it's best when you run on a treadmill for 2 minutes and then walk for 2. I couldn't always do that so I would jog at a slower speed which can do the same thing. You just have to keep that heart rate up. Utilizing the ellipticals can be a really big plus!
Weight training is great if you haven't done alot of floorwork ( meaning you haven't done ab exercizes on the floor). These are great for toning rather than burning fat. You still need both to get the best results. If you have done floor work before than your better off staying that way because you get more out of it. For those that have back problems like me a stability ball works wonders. So does something called the Bender Ball it can be purchased at any Target along with the stability ball.
I hope you see great results with what I have given.