What can I do to strengthen and whiten my teeth? What toothpaste would help the most? (Photos)

Recently, I’ve been more self conscious about my teeth. My first problem is that the edges of most of my teeth are starting to appear translucent. I’ve used Crest Whitening Strips before to whiten my teeth so I don’t know if that’s part of the cause. I’ve heard about remineralization of the teeth, so would that solve the translucency? Another thing is that the lower part of my bottom teeth are more yellow than the rest despite my whitening strips efforts.