How to tailor a shirt
There is definitely a time and a place for tailors, but some of those quick fixes to alter a shirt ever so slightly are super-easy to do at home. It's just four easy steps to make your tops fit perfectly. It's a great trick to have up your sleeve when you fall in love with a top and the fit is just slightly off.
Matching thread for your sewing machine
Pencil or chalk
Before you start, make sure your shirt has been pre-shrunk (if needed).
1. Measure and pin
Turn your shirt inside out and try it on. Determine how much and where you want to take it in. Remove the shirt and lay it flat on the floor, with the side seam of the shirt completely flat. Pin it in place so the shirt doesn't slide around as you sew. Make sure you match up the underarm seams.
With your shirt still inside out and pinned in place, use a pencil or chalk (something that will wash out) and make marks along the shirt where you want to sew. Follow the line of the original seam, keeping your marks equal distances from the original seam as you mark along the shirt.
With a straight stitch, sew along the side of the shirt from the hem, over the armpit and down the sleeve, following your marks. If your shirt has cuffs, like mine, gradually angle the new seam toward the original seam as you get close to the cuff until you eventually run into it and begin sewing right on top of the original seam. This will help you avoid any tucks. Repeat for the second side.
3. Cut and finish the edges
Once the sides are both taken in, try on the shirt to make sure it fits properly. There will be some bunching in the underarm from your seam allowance, but try to ignore that. If the fit is wrong, unpick the new seams and try again. If it's good, cut the seam allowance down to a 1/4 inch and then zigzag or serge along that cut edge to finish the raw edges so they don't fray.
If you need to hem your shirt, unpick the original hem using a seam ripper, and then fold up the bottom of the shirt twice (fold over once, and over once again). Using an iron, press the folded edge in place, and then sew around the entire bottom of the shirt with a wide straight stitch, securing the folded edge in place. And you're done!