From experience, what is the best way to lose weight?

So two years ago I lost a total of 34 pounds and gained a total of about 10 back, which makes me pretty freaking upset. Yes, I do not work out, but I only eat like two meals a day and drink almost a gallon of water a day haha. When I eat out, I try to choose healthy menu options. Would you guys suggest nutrisystem/ Jenny Craig? A specific workout to target cellulite? A personal trainer is extremely expensive haha. I just want to be skinny! It is so hard to maintain my weight :(. Even though with the weight loss, I am still considerably overweight for my height/age. SUGGESTIONS!
From experience, what is the best way to lose weight?
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