Do I need a fancy costume?
No! Not all characters require elaborate dress-up. It's also possible to make a difference between your character and your costume part of your character's story.
For example, ten years ago a guest came as a space alien who had devoured the body of the "real" person, and was impersonating her.
In the midst of the fantasy, let's get real: this does not mean you could dress in a business suit and be Darth Vader; a "willing suspension of disbelief" won't go that far. Please pick a combination of character and costume that will help others accept you in that role.
Of course, you can always come as yourself. That will make the costume simple.
How much can I dare?
I encourage you to Dream, Play, Share.
However, we're going to be in a public venue. "Mundanes" might wander in at any time. Also, it's cold in December, and part of the story may take place outside. Please be discreet.
Any other tips?
If you're part of the story, you'll get a pouch attached to a cord necklace. You can wear it another way if you wish, but make sure it's clearly visible. Remember, the pouch will tell the other guests that you're in the story.
You'll be handling things: cards, beads, dice, etc. Be prepared if your costume has gloves.
Some ideas: cut off the fingertips of any gloves you have to wear; use latex gloves; get someone to be your servant.
Allow plenty of time to get into your costume. If you've got something new or elaborate, try it on beforehand; give yourself time to fix problems.