A good way to keep in touch is by text messaging on your mobile phone. Phoning from abroad is relatively easy from call boxes. If the family have a computer and you can get to an internet cafe this is another way.
There are so many ways - texts, phone calls, emails, Skype, or old fashioned postcards and letters. Postcards are nice because they show what you are doing and where you are.
You can stay in contact with family using a number of tools. You can call them on the phone, send them an email, use a video chat, send them an instant message, or send a postcard!
When traveling, Skype is always a very unique and personal way to speak and see my loved ones at the same time. It is amazing to be in a foreign country and then turn on my computer and see my Granny sitting in her kitchen in Utah.