Well, my birthday was only a few weeks ago, and it was lovely... so I think I have this topic under control!
1) Set reasonable expectations. Not everyone will remember. Some packages may be late. Be grateful for the gifts and cards you do get, and don't dwell on the missing ones.
2) Plan ahead, but don't get fixated on those plans. (We have baby-sitter issues some years.)
3) Sushi makes everything happier, at least for me. (And there's a decent sushi restaurant 2 blocks away from us, so it's very easy to make me happy...)
4) Don't eat so much that you'll be dieting for the next month. Think about how you'll "spend" your calories for the day.
5) Having said that, do indulge to a moderate amount.
6) If "alone time" is an important part of your day, absolutely demand it today.
7) Update your Amazon and Loopy Ewe wishlists at least two weeks before your birthday.
8) As much as your family will let you, sleep late.
9) This is a great day to cast on for a new project.
10) This is also the day that I start seriously thinking about Winter Solstice Knitting...