I've been working on bettering my sewing skills for the past year or so (intermittently). I have found it really helpful and wanted to share some very basic tutorials on alterations. The first tutorial is how to alter a garment made of jersey or stretchy type material. Jersey material is very easy to alter and wear especially if you want to continue the seam into the arms. With less stretchy material, if you alter the arm holes without taking the garment apart then you restrict movement.
My husband was nice enough to play model for me since I had honed my skills altering all of my clothes. I use this technique for tops or dresses that need to be taken in a size.
Here is the before. It's about 3-4 inches too big.
My first step is to turn the garment inside out and pin it. I don't take a lot of care while pinning it. I just try to get a general idea of how much material I need take off. After it is pinned, take off the garment. If you are doing this yourself, find a similar item in your closet that fits well and pin your item based on that.
Once you have it pinned, I measure both sides to ensure that I am taking in the same amount on both sides. I also make sure both sides of the garment are lined up exactly. You can even fold over the shirt so both pinned sides line up and you can make sure you are taking in the same amount of material on both sides. Then using matching color thread so sew the sides where you pinned on the inside of the shirt.
Try it on and make sure everything fits well and you can move around in it. If it doesn't then rip out the stitches and try again! If it does, good work you saved yourself some time! I am always really careful about measuring because I hate going back and having to do it over.
As you can see in this picture, the new seam has been sewn. I then cut off the extra material leaving about 1/4" left.
Use a zigzag stitch to hem right along the edge of the material you just cut. I use the zigzag stitch because I do not have a serger and this helps to finish the edges so they don't fray.
Trim the excess thread on everything and you are done! I also typically backstitch right at the end of each seam I do to ensure the seam doesn't come undone. I am hoping to work on hand sewn hemming and altering a button up, too!