It's a little hard to answer without knowing what you have tried before (if anything), how much weight you want to lose, how old you are.
In any event, the first thing would be to eliminate the refined carbs (sugary sweets, white flour products [bread, pasta, crackers, etc.], white rice, chips) in favor of carbs from veggies, fruits, legumes and whole grain products.
Some people have success just doing this and restricting carbs to under 100 grams per day. And if you haven't tried it before, I would start here.
In a nutshell, Atkins initially restricts carbs to 20 grams per day and then starts slowly increasing them again. Weight comes off faster, but eventually you are going to have to find a way of eating you can stick with for life. So (depending on how much weight you need to lose, whether you have dieted before) a slower, more conservative approach may be the way to do it.