Whew, Idon't know about Vlogmas. We are more of a summer channel and tend to take a little time off around the holidays.
If you are going to do it be prepared: start filming several days in advance, batch those videos and give your audience the absolute best quality content you can. That's about the best thing you can do regardless of season. Go all-in on serving your audience that which they want to see!
Good luck!