I wear it 34a it used to drive me crazy. I had super low self esteem. I got some super push up bras, wearing really padded bras with a strap perfect thing in the back works wonders. I've stopped caring as much though. I realized that there's a lot of other girls with small boobs and it really doesn't matter that much. I mean I have my days where it still bothers me, I hope to one day get implants lol I've had it planned forever, but wearing push-ups with something to bring the straps together in the back gave me the best results.
Take an eyeshadow that is a couple of shades darker than your skin tone and a small brush and go in between your breasts on both sides and blend it really well also put a bit around the breasts too and make sure to blend the key is blending until it looks natural! Hope this helped!