I love holidays, and I'm always looking for new holidays to add to my personal calendar. Every year or so, I feel moved to look for interesting days to celebrate, and I adore Pagan date books that have at least one thing listed for every day (and I totally need to get a book and cultivate my own book of days!)
But in my search for interesting holidays, I always stumble upon some UPG or created holidays. One that often pops up on my social media is Wolfenoot (which if you haven't read about...you need to, it's adorable). And I recently found a whole set (kind of like the Advent or 12 days of Yule) where someone described a set of days devoted to the Norse nine worlds.
And invariably, when talking about created holidays, there will be comments that those aren't 'real' holidays, and some people feel like creating your own holidays (or celebrating a modern 'created' holiday) is somehow tipping into realms of pop culture Paganism or Chaos magic, where you can just make up whatever you want (which if you aren't aware, I'm a huge fan of, but I know it's a contentious subject for many people)
But here's the thing. All holidays are created! If you go back far enough, someone (or a group of someones) decided that this specific day would be a good day to recognize this person/event, and they started doing it.
If you search for holidays for any given date, you will find a whole list of days, from long established traditions to very new ones (like Talk Like a Pirate day). There are holidays with tons of followers and some with only a few. Like anything else, popularity can be hard to predict, but once something catches on, it becomes a whole thing, and suddenly everyone is talking about this particular day.
One of the great things about created holidays is you can create a holiday to recognize whatever you want. If you have a deity you work with, maybe you want to dedicate a holiday to them. Or maybe you have a holiday you grew up with that doesn't really fit you now, but you want to build a new tradition off of it (like Friendsgiving). You could build a holiday around your favorite myth or story, creating traditions that represent different parts of the tale.
Which is great, as there are so many aspects of different deities and traditions that have been lost to time. When I read about a deity who is barely mentioned in the stories (or maybe who is literally only known as a name), it makes me a bit sad, but also like I want to know more about them. And I get that the more well known and popular deities are the ones that we still have holidays to honor, but that doesn't mean we can't create holidays to honor other deities that we work with!
Whether you are creating your own holiday from scratch or taking someone else's holiday idea and building upon it, there are a lot of great things you can work into your holiday. Of course you first have to start with a date, and finding the right day to celebrate on could mean figuring out a date that would fit with any lore that exists, but it could also mean finding a day that feels right (perhaps it involves a specific number or is during a certain season...or maybe you want it near another holiday or at a time of year that doesn't have much going on).
Then you can start to think about what things are done during your holiday. Foods are a great place to start, perhaps there are dishes that should be served or a style of eating (like having a picnic or all cold foods). From there you can expand to other decoration ideas, like a color that represents your holiday or decorations that might be hung.
And then you should consider activities. Are there ritual actions that would fit your holiday? Perhaps it is a time to tell tales or sing songs or create art. You might keep it general or you might want to dive in and create a very specific thing you do as part of the celebration (like decorating and hiding eggs or carving pumpkins).
Just remember, the whole point of the celebration is to recognize something, so the things you pick to incorporate into your holiday should all relate to it's central theme. Those connections might not be obvious, but they should be there.
And finally, decide if your holiday will be a personal one, or one you share. You can absolutely create private holidays, special days of celebration that are solitary expressions of your path. This might include days of personal significance (like honoring any initiations you might have gone through), or just private rituals that you do with your deities on specific days.
But you might decide you want to share what you've created with others who might also like to celebrate with you. In this age of social media, you can easily post your holidays online, or you can host a gathering (you can either explain everything ahead of time or let people know you will elaborate on the purpose of the gathering once they get there). You could even invite others to help you create some of the aspects of your holiday!
Just remember, if you go back far enough, all holidays were created (and some of the holidays we recognize as Pagans weren't created as long ago as you might think...), so there is nothing wrong with creating the holidays you wish you could celebrate or ones that have personal meaning for you.