What kind of diet??

Okay so I’m 5’5 and I weigh 164lbs. My goal is to generally just look good in my own opinion, but if I had to lose a certain amount of weight, I would guess that I’m wanting to lose about 20lbs. I’m 19, and I’ve never really had a workout plan or a strict diet. Should I be counting calories or carbs? And how often should I be working out? I want to see results as quickly/healthily as I can! Please give any advice! Thanks! 💕💕