birthday make sure you let your hotel know, don't just assume they will know just from looking at your details (I've done this before and was like oh no one cares that it's my birthday..) Some hotels take guests birthdays very seriously so this could result in anything from a free room upgrade to a bottle of wine or a fruit basket. Or even something simple like a personalized desert or special cocktail.
When I stayed at Rostrevor in Barbados for my 30th I got a
room upgrade and the best bottle of red wine ever, I was sooo happy as I actually wasn't expecting anything at all, I was even baffled as to how they even knew I liked red wine.. (then found out they'd been communicating with my friends who had told them) they were absolutely lovely to me, I do like Rostrevor and not just because they gave me free wine... well maybe... no, it's actually a fab hotel.
Also let your airline know it's your special day they may be able to do something nice for you, even if it's simply a free glass of bubbly on the flight and to be fair you only really need one because all them bubbles mixed with the altitude will have you all giggly very quickly.
So basically the possibilities are endless it just varies from hotel to hotel and if you're feeling really cheeky just ask for stuff and then say the famous line "Oh but it's my birthday!" lol