Find a style that fits you well. Nothing will flatter you if you feel uncomfortable or the swimsuit sags on you and fails to make the most of your figure. Remind yourself while shopping for a swimsuit that you deserve something of quality that you feel good in; don't settle for less.
Look for styles made for curvier figures. For example, the 50s style one-piece swimsuits were made to accentuate and celebrate curves and are very flattering. They have lower hip rises, higher waists and provide plenty of upper body support.
Look online for seamstresses who specialize in making swimsuits based on earlier era styles. This has become a specialty niche that allows for the seamstress to enjoy their art and lets you get hold of a great, unique piece that is tailored to you and your precise measurements.
Shop for your body type. Not all plus-size bodies are alike—your figure may be an apple, pear, hourglass, etc. Figure out which part of your body you want to accent most.
Try wearing brighter colors on areas you want to emphasize, and darker colors on areas you want to de-emphasize.
Find your body accent. Strut your stuff and show off your favorite parts of your body. If you want to show off your chest more, wear a lower cut swimsuit with a longer hip side. If you want to cover your chest, find a high-necked swimsuit.
Avoid wearing a high-necked swimsuit. This style can look (and may even feel) rather confining and is not particularly flattering. Instead, try something with a sheerer fabric and cut above a normal neckline.
Consider your color palette. Which colors look good on you, and which ones make you look sickly? Figure out whether you are a winter, summer, spring, or autumn. Choose colors that complement your skin tone and make you look healthy.
Try ruched fabrics and wraps. Ruched side panels can enhance your silhouette, and ruched fabric and wraps in general can be flattering and more adjustable in size.
Find something that supports your chest and feels comfortable. You want to be able to swim, walk, and play comfortably in your swimsuit, without constantly pausing to adjust. In the dressing room, stretch and try lightly jogging in place. Will you feel comfortable?
Check to make sure that the straps are comfortable and the bottom doesn't ride up.
Look or fun patterns. Bold, bright patterns look flattering and festive. Choose a print with shapes and colors that make you feel happy. If you're a little pattern-shy, try swimsuits with solid panels on the sides.
Experiment in the dressing room. If you aren't sure about a swimsuit on the rack, try it on, just in case it looks awesome on you. You may be surprised at what you can pull off!
Remember that different brands size differently. You may be a size 16 in one brand and a size 18 in another. This is okay. Be willing to go a size up or a size down from your general size, in case one particular swimsuit is cut differently.
Don't fear the bikini. New styles such as fatkinis and more bikinis geared towards plus-size women are hitting the market. They include flattering high-waisted bottoms and plenty of support for your chest. Your body is beautiful and you are not required to cover it up.
You can also buy the top and bottom of your bikini in different sizes if needed.
Find swimsuits that you personally love. What are your favorite colors, silhouettes, and patterns? What sort of swimsuit makes you smile and look forward to wearing it? Search for swimsuits with details you like, so that when you go out to swim, you feel confident and beautiful.