Pear shape: You have larger hips & thighs than your bust and shoulders. Choose two piece plus size swimwear (Bright print on bust top and dark coloured bottom) or empire waist swimdress.
Heart shape: Your bust and shoulders are larger than your hips and thighs. Swimdress or skirtini would do the trick because it will hide the uneven body proportion.
Hour Glass shape: You have a curvy body. Your shoulders, bust and hips, thighs are similar in size except your waist. Tankinis with halter neck and dark coloured brief will help minimize your shape.
Boy shape: with no waist and flat rear, broad shoulder. Plus size swimwear in two piece (skirtinis) with halter neck will create curve and make you look more feminine.