Have you calculated the number of calories you should eating/day? That's the start.
Do you have an exercise program going? The easiest way to lose weight is via a reasonable diet, focusing on lean protein, whole grains, low/no fat dairy, lot of veggies and fruit (whole fruit, not juices), "good" fats and moderate exercise.
If you would care to let us know something about your current routine, we might be able to help "tweak" it a bit.
Do you know if you have any medical issues that could cause weight gain and/or make it difficult to lose? Some of them could include hypothyroidism, insulin resistance, PCOS and others.
We also have a challenge going on right now; feel free to join us.
http://www.medhelp.org/posts/Weight-Loss--Dieting/THE-CHALLENGE-RAISING-THE-STAKES-/show/1294159