An easy way to avoid your zip to open is to hold it with an elastic band.
If you don't want to sew a button that is falling off, use some clear nail polish.
If you want to remove oil stains from clothes apply talcum powder to the stains, leave it overnight and it will absorb the oil. After this you can wash the clothes as usual and the oil stains will be gone.
Use a bread clip to fix your flip flop with split holes.
If you don't have an iron (but you have a hair straightener) you can use it to iron your collar.