The first, is simply duct tape, which is awesome for all sorts of things. While visiting a friends classroom I noticed that she had a carpet for students for sitting on the floor- however students will pull up carpets edges, pull them apart, run and slide on the carpet, it can be a mess! This teacher friend of mine had her carpet taped down around the edges. Simple but effective! No more sliding, less distractions! In the photo below you can also see my duct tape line for students to line up on at the end of each class. Duct tape for the win!
Another great trick I recently figured out was using a squishy knee pad (typically used for gardening,) can be brought indoors and used when loading or emptying the dry rack! No more knee bruises.