Alterations repairs
There are many different types of repairs, however one that I do a lot of is what I call Bond and Darn. Buy yourself some Vizaflex which you can get from any sewing shop. You only need a small amount, because it is expensive. Cut some fabric out that matches the tear in the garment and iron it on to the sticky side of the vizaflex. Then peel off the back sheet and iron this on to the garment on the wrong side under the tear. Try to have the tear pulled together. Now find some cotton that matches as close as possible to the fabric. Blind hemming thread is perfect. Look at the grain of the fabric, and change your stitch length to a very small stitch length. Darn back and forward in the weave of the fabric, never going over the same section twice. Move back and forward across the weave. How well it looks will depend on the type of fabric. Wool and linens are the best.
Happy sewing
Judith aka genie