I want to share one of my favourite fixes with you.
Ever made a top or dress thinking all was good with the fit, only to find the neckline or armholes gape? There is plenty of advice out there on ways to avoid the problem before you cut the pattern, but none tells you how to fix it after you've made the garment! You don't want to waste all your good work but how can you fix the problem?
Hat elastic is the answer! Hat elastic is a single core elastic - only one strand of rubber (or whatever they use these days). You thread a piece of hat elastic though the channel of the neckline or armhole seam and gently ease it in until the gaposis is gone. Tie off the elastic with a reef knot when you have the easing just right. A reef knot should not come undone - a granny knot would not stay tight. If you don't know what a reef knot is, have a look here:
You want it to pull in the excess fabric, but not so much that you cause the neckline to gather up. it is quite surprising how much you can reduce the size without seeing any gathers.
This technique works really well with ready-to-wear too. Often RTW garments don't have darts where they should and that can make the armhole gape. It's also great for jumpers, if you feel the neckline is unflatteringly low or wide.