Use original packaging if possible, that way you can keep count of all your special decorations, it also gives you the opportunity to label them, from year or person they are from!
Use clear plastic storage bins to keep like items together, making it easier to decorate next year, and easy to see what’s inside. All your tree lights and extension cords together, outside lighting and extension cords in a separate bin, so next year you have it all together! Then label your bins.  The plastic bins will also help protect your precious memories/decorations from the elements, and dust.  Use the Silica packets found in purses and shoe boxes in your bins, helps to protect from moisture.
Keep a separate “forgot it bin” so when you find a forgotten decorations ( or 2), you can put them in that bin and take it to your storage area at the end of January!