Dieting?

Okay, so I thought I've been losing weight bc my clothes have been baggier on me but I gained weight. And I know doing dancing school and going to the gym can build muscle which weighs more than fat but I want to lose weight like 20-30 lbs. So besides no sodas are there any certain foods I should totally avoid all together if I want to lose weight ? And any other tips will be helpful. I did some looking on Google but every website says something different. I weigh 163 lbs right now and I'm covered in stretch marks, I don't feel happy with how my body looks right now. So any help or advice will be appreciated. (These are the best somewhat body pictures I have )