This one is simple.
Keep an Advent file. Bookmark good stuff on the computer, and keep a paper file.
Toss good ideas into your files as you stumble upon them. When you're halfway through Advent, or seven days into the Twelve Days of Christmas, and you discover a great new idea, don't kill yourself trying to implement it right now.
The idea will still be there next year. Most likely, you and your kids will still be here next year, too.
So, don't try to do it all.
That's what files are for: to hold all the great stuff you're not doing at the moment, but will, one day, do.