Consider what you are storing there and that will help you decide how deep your shelving needs to be. Be careful about large bins as weight should be a consideration. There are lots of fun baskets and lightweight cardboard boxes you can store things in. Don't be afraid to use colour to make it fun or to help you find your items. Consider leaving one wall or part of a wall open for hanging items. Closets are great fun, enjoy your project.

I use underbed storage bins in 24-inch deep cabinets and have the shelves closer together than normal. These bins only allow one layer of holiday items in them, so are really easy to see what you have as you are decorating. Plus mine are color-sorted as I change up from year to year and the opaque plastic lets me know what colors are in what bin. I'm sure this comment is as clear as mud.

Thanks so much! Great idea about large bins. Sometimes bigger isn't always better. And I love the color sorted idea.

If you have larger storage, just make sure it goes on the floor. Also, see through drawer units can be great, that way you don't have to lift a box down to get at what you need. Things like scissors and tape are used often. Less often used items at the back or top.

Make sure that you have wide enough space in front of the shelves to pull out the bins.

I collect Christmas ornaments, many of them antique or vintage, so I don't like the plastic boxes. I have a huge stack of archival ornament boxes in a couple of sizes from the Container Store. I've been very happy with them. Ten or twelve can be stacked and they're sturdy enough (and I guess the ornaments light enough) that it's not a problem.