I always slip bolts/nuts back onto the things I take apart if possible, and any others I will also just ziploc and mark with a sharpie. Pictures will help, especially when it comes to little things like seeing where something lined up i.e. pedals, brake stay, etc. Where wiring was running from/to... Anything that one doesn't usually think about when pulling things apart.
It is nice to have pictures when ordering parts and things to double check on what you had on hand.