Depending on what kind of space you have access to will change and mold these ideas into what you are needing. As for me i have an old 2 stall garage built in the 1910s on a concrete slab that was not taken care of that well but still holding together! because of this there is a lot of air leakage, no insulation, cracked concreted with some up heaves in it (there is electricity at least!). Due to us leaving this home in the next year or two i do not want to make anything too permanent or spend too much as i will need it at the next location to make my "dream shed" so to speak. Living where I do means heating this area is of great importance as it will get very cold everything will freeze up quite quickly. I have so far got a hanging system set up for drying stretchers / hanging wet animals to dry but made it where i can unscrew it and it'll come right off so i can bring it to the next location. My father and my fiancees father are carpenters so i grab what leftover insulation they have and am slowly filling the walls and rafters. i also added 6 Mil plastic to the walls and ceiling to help with air leakage problem though i did leave a few holes for venting. i Will be using a propane heater but it will be used correctly so i will not get poisoned by it, also i have a carbon monoxide detector just in case. Lastly (for now) i will be placing a vinyl flooring (free from carpenters so most likely a few different ones) on the floor to help keep stains off the concrete, make it easier for cleanup, and to help keep it a little nicer as you wont be standing on cold concrete.