I actually did this a few months ago, just as the weather was turning cold. I'd been planning to do it for a while, but I had a sudden urge to drink as much tea as humanly possible... ASAP! Having a well-organised tea cupboard makes that a much more pleasant experience of course, so I finally got down to it.
As you can see, before the cupboard had two shelves -- the bottom one for tea and the top one for storing unopened condiments, etc. There is way more tea than will fit on one shelf, so it's all stacked up higgledy-piggledy. It's hard to find anything, and it's annoying when you grab one thing and five more fall out!
So... Husband went to our local big-name hardware store and bought a shelf and some lugs. He cut the shelf to fit and installed it so now we have three instead of two!
All of the teas we drink the most and the equipment are on the bottom shelf, and other open teas are on the middle shelf. Unopened ones are at the back. I also went through and labelled all of the tins so we can find things easily. And of course, I made an inventory of all our teas, because lists are my thing! It's on my Listography here.
Happy tea drinking!