If you are larger chested, you might find that you need some support under the cups to keep everything in place. Before you sew your side seams, you might want to try adding a piece of 1/2" wide elastic onto your seam allowance, under your cups. For those of you who followed the Oooh La La Sew Along, we'll be doing the exact same thing we did there! This step is completely optional!
See the yellow dashed lines? That's where I need some more support. I am going to apply the elastic right along the seam allowance where the bust cups meet the body of the swimsuit.
When you get to the center, with the needle down, lift the presser foot, gently pivot, and continue on. You could easily do the same thing by adding clear elastic into your seam line.
If you need some extra clarification on this step, Visit this Post, which talks about it in more depth. Once you have zig-zagged the elastic on, you can top stitch with a zig-zag stitch, or twin needle, or just leave it loose.