One of the tough lessons I'm learning with selling things online is that you have to plan far in advance when making items to sell that are geared toward a particular holiday or event.
Despite having a lot of great ideas for Valentine's Day items for my shop, I only managed to get one jewelry set listed and I missed my opportunity. I should have made more for the shop a month or two ago. By the time I figured out how to make these red and black tatted hoop earrings, it was too late to have them online in time for Valentine's Day. They will still make a great addition to my shop, but I will have missed the holiday they were best suited to.
It makes sense when you think about it. People do their online shopping earlier than if they were to go to a physical store. They have to make sure there is enough time to have the item shipped. It's also important to have enough of a selection of items that people won't just take a quick look at your shop and then leave. If your items are bought by someone in another country, they're going to shop even earlier since shipping takes so much time.
Inc. wrote a great article giving 6 Tips on Preparing for Strong Holiday Sales on Etsy. I like how they remind you of how big retail stores prepare for holiday sales. I know it's easy to get annoyed with stores that put up Christmas displays before Halloween, but the reality is that it works. If you don't have the items in your shop when people are ready to buy it, you may never get that opportunity again.
Etsy does a blog post each month with information from their Merchandising Desk with news and tips on upcoming events and holidays as well as trends they've seen. This is a good resource for planning ahead. Many sellers say that the information in those articles can help you to get more noticed for treasuries and the Etsy front page. The Etsy Blog is a must-read for those merchandising articles as well as features on various sellers, and how to quit your day job. You've got to be willing to do a little research in order to improve your shop and not miss sales opportunities.