This is from a series originally posted on my original blog: Seefahrer Thayer. While I don't recommend it, you can view the original posts here. Because the content had value and useful tips I've decided to repost them here, however, they've since been heavily edited and updated.
Just a side note:
when traveling abroad (and backpacking), unless you plan to spend every day at the beach, don't pack a beach towel. It takes up too much space when you could easily get by with a hand towel. I've seen a lot of people trying to squeeze these huge, wet, space suckers into their overstuffed bags and it's just not necessary.
When I travel, I bring little trinkets form home to give to people I meet along the way. These are a must, and you really can't bring enough. In fact, bring 3x what you think you'll need. I'm less than a week in and already I'm almost out of my Community Coffee packets. I have a lot of New Orleans postcards left, but everyone's loved the coffee. They're nice to give away to people that help you- like Don at central station in Belfast, or friends you meet along the way.
Also, an external battery is great. I can't impress enough how much of a lifesaver it's proved to be.
And of course, bring a scarf and a blazer and you'll fit right in here.