I found organizing by event to be the most helpful. I had all welcome party items together, then ceremony in a box, then cocktail in another and finally reception. I labeled everything in the boxes and individual things wrapped. I had a destination wedding so I flew with a lot of stuff mostly frágil so we had to wrap it to protect it. Everything was label by event (ex: reception), the item it was and how many (ex: table numbers - 5) I was able to stay very organize while at home and once we arrived there.
When the boxes started to seriously pile up I ended up taking everything out of their larger boxes and arranging by purpose. All of my candles/votives went together, while sweetheart table decor had another box, etc. Then I labeled each box clearly with a sharpie.
The labeling was HUGE because we had a lot of hands on deck for set-up and people were able to quickly find items without having to ask me about the contents of each and every box.