Which bikini is most flattering all depends on your body shape. If you are below 5ft 5 then you probably don’t want to make yourself look any shorter so go for a higher cut bikini or swim suit, the short type bottom with shorten your legs. The string bikini bottoms are also good for this. Also if you are worried about your thighs again avoid the short type bottoms with will make them look wider. If you are small busted then opt for a string bikini or go for a padded top to add some extra shape. Alternatively if you are large busted then look for a bikini top with built in support and with wider straps. You could try a halter neck with built in support which will be good for shaping.
A tankini (a vest top) is a good option for covering your tummy if you don't feel confident to show it, then you can roll it up for sun bathing. Belted style bottoms will draw attention to your tummy so I would avoid them if you don’t want to draw attention to that area.
Swimming costumes are very fashionable this year so that could also be an option if you are a bit conscious of your tummy. Again high cut legs will be more slimming.