My sister is due to have a daughter in a couple weeks. This will be my first time as an uncle. Any advice?
Spoil your niece rotten. Make a list of all the times your sister got on your nerves when y’all were growing up. Each time you give your spoiled rotten niece back to her cross one item off the list. This is your time to seek sweet revenge so go for it! 
Seriously, she will have you wrapped around her little finger the first time you lay eyes on her. Enjoy your sweet niece. She really needs all those noisy toys she can only keep and play with at home.
Being an uncle is incredibly fun.
Never, ever, be “too cool” to do something she wants to do. You’ve seen those pictures on the internet of awesome dads and uncles dressed up as princesses in public to make their little girls happy? Do it. I guarantee you’ll have fun.
Show her the things you love, but don’t force her to love them. Learn about the things she loves, and find a way to do them together. Go to tea parties, get your toenails painted, learn about My Little Pony, scour every store in a 100-mile radius to find her a Rey action figure. Spoil the hell out of her and make her important.
Above all, have fun. And congrats!
Is she still in Florida?
Being an uncle is great. Don’t waste it.
Dude, if you are going to have a niece, it means that some asshole is taking liberties with your sister. What kind of brother are you?
Congrats to all. Spoil her rotten, thats what Uncles are for anyway.
Congrats!
If there are any other uncles, do whatever you must to be “the favorite uncle”.
My sister’s eldest recently married, and he asked me (the favorite uncle) to solemnize their vows. My brother has always had a problem with me being the favorite, but oh well.
Be avuncular. Except, you know, in a good way.
Very close to my three nieces. Not really changing diapers, but was regular night overwach, when their parents wanted some fun.
One is now getting BA in nursery in a couple of months, and since I have some problems that way, she is more than useful. I fix their computers also, FTW.
I’m an uncle who had a lot of fun with my nephews when they were children. Now I’m that FAVORITE CRAZY OLD UNCLE they love and talk about!
Nice work if you can get it. Have fun with this!
Being an uncle is … meh … being a great uncle is fantastic … too much fun when my niece has to search my rig to make sure I’m not stealing any of her kids.
Becoming a great-great-uncle this Oct. Still haven’t met the great-niece. So, no change in anything expected.
(OTOH, I still have a niece that calls me her favorite uncle. That’s cool.)
You’ll have to wait a few years for this to really have an effect, but be sure to tell your niece every embarassing story about your sister that you can remember. And if your sister tries to tell something about you, don’t just agree, but ramp it up so that you sound like the most obnoxious brother in history.
One of your jobs as uncle to a small child is to borrow him/her for an afternoon or evening so mommy & daddy can have some alone time. During this time, you will grant access to unlimited amounts of sugar and say no to very little, if anything.
Then when your time is over, you will return the properly buzzed out child to his or her parents and rest comfortable in a job well done.
She has been back in Maine for a while and just gave birth this morning. I went to see them after work, they both doing really well.
Congratulations on the right number of fingers, toes and smiles 