As an adult, the pressure of birthdays falls into our own laps, for the most part. It happens quickly. Suddenly birthdays aren't days spent luxuriating in the fruits of our parents' labour. They are upcoming events we have to plan to ensure we don't feel lonely/unpopular/unloved, as we mark the transition to another age. Some birthdays are, of course, worse than others. 18, 21, 30, 40, 50 and beyond all bring with them a similar expectations of fun that New Year's Eve does. Some of us may be happy to equate growing up with the end of over-the-top birthday celebrations. Others may still be trying to wrap their heads around how to acknowledge their aging with an appropriate level of ceremoniousness, while maintaining their dignity (i.e. not booking out McDonald's/Sizzler/asking the 'rents to plan their 28th as a reenactment of their 8th).
Here, I present the definitive list of GOOD ideas for your adult birthday. Some are silly, some sensible, all very helpful. Happy Birthday to you.

Plan a party, you go-getter

And what if it's a big, meaningful year and you do plan to have a big old party thank you very much? Then good on you!
Make sure you plan well ahead to avoid the thing creeping up on you. What do you imagine when you think of this party? Where is it? Who's there? Be led by the images that you conjure instinctively when thinking about it. Don't worry about asking loved ones to take on a bit of a role to ease the burden -– ask your savvy, planner friend to send out the invitations etc. Make sure the food is all the stuff you love to eat, and that the champagne is quality.
If it's at home, get a playlist of your favourite songs (a clash of genres, sensibilities and good/bad taste is fine). Invite who you love and who loves you. Buy a new frock/suit/hawaiian shirt to mark the occasion. Ask your partner/dad/best friend to make a speech and say wonderful things about you, and to include one humorous anecdote that veers closer to endearing, rather than mortifying. Kick up your heels, enjoy the spotlight and have a great time. Get a bit carried away with the sentimentality of this day; so many people didn't get to reach the age you are marking but wanted to. Feel fuzzy and grateful, and then swiftly get back to more bubbly and adorable, inventive dancing.