Button 1 was a decorative button on the back of a pair of shorts. This was a flat button with four holes and didn't need to be sewn on particularly well, as it doesn't hold anything down and isn't functional.
Button 2 was on a pair of chinos, at the top of the fly. This one needed to be sewn on very firmly, as not only is it only a two-hole button, but it is also a functional button. The method I use is to double up the thread, sew several loops to attach the button, knot it off, then sew several more loops, before tying it off finally.
Button 3 is a covered shank button, meaning it is covered in fabric that matches the dress it is part of and has a small protrusion on the back with a hole through to attach it to the fabric. When these come off, they often tear the fabric of the dress, meaning you have to repair the rip as well as reattaching the button.
My final repair was a small hole in the skirt of a chiffon-esque dress. This was a tough one, trying to sew up a hole without pulling the delicate fabric into a single point. I'm not sure how obvious this will be when I put the dress on - I'll just have to test it later!
