One that comes to mind, is instead of painstakingly peeling garlic cloves, to put them into two bowls of similar size, and put the bowls together with rims meeting, and shake them hard. The peelings come off so easily after that!
For frozen food bags I don't open them all the way across with scissors. I cut a strip 3/4 the way along the top and about 1" down. You can then use this to tie the bag up again, by gathering the bag together, twisting the strip around it and through the loop you create - then pull tight.
Use dry tea bags to mop up small spills.
I've just figured out how to hack a solar garden light to work as a soil moisture sensor instead. If I see any lights on at night I need to water the garden. As a bonus - it can use "dead" alkaline AA batteries to power it, and should last several years on one dead AA.