Social Network Service (SNS)
This is very fundamental. Now everyone uses some SNS such as Facebook, Twitter, and Google+. Travel friends join each other, show each culture, and photos. If you have your personal cards for them, your travel friend can join after you leave.
Picture Cards
If you plan to travel, bring a few picture cards that indicate your local cultures. When you talk with others at hostels, you can indicate them with your cultural contexts.
Music Playlist
You can create your music playlists on music services such as Spotify, iTunes, and Youtube. You can talk your favorite music with your new friends. Especially, if you have some playlists in your countries, they may be very exotic for new friends. You can listen on your smartphones too.
Coins
If you have some coins after you exchange money from your countries, you can bring them. They may not useable in your destinations, but you can give them for the friendships for your new friends. Also, the designs on coins indicate the fundamental things of your nations. They must be good when you talk.
Candies
If you can bring a few small candies from your countries, it's a good idea to give and let your friends taste. (Some countries prohibit to bring food in domestic for security reasons. Please check about your destinations.)
Anyway, if you travel for a long time, it's better to keep your package small. The best is to keep all in one backpack. Don't buy expensive and big stuff for this purpose. In many cases, they are just waste.
"Happy" (2014)
by Pharrell Williams
In fact, to get a travel friends are not easy. Your cultural context and common sense make your new friends something wrong. These make them just one time friends. If you can get a permanent friend, you are lucky. It sounds "Happy."
