According to clinical psychologist, Dr. Rob Dobrenski, the largest barrier of long-distance relationships is lack of face-to-face communication. Couples invariably need not just emotional and physical intimacy, but also the ability to resolve conflicts. This is significantly easier when you can see your partner's facial expressions and non-verbal communication. Phone, text, email, Skype, Morse code, Instant Messaging, Facebook updates and carrier pigeons all still require a lot of guesswork to really gauge what's going on with your partner.
This is especially true if couples aren't already the greatest at directly and confidently stating their feelings. Video chatting is a better option than a traditional phone call, as it allows you to read some of your partner's non-verbal communication. Aside from just talking to each other regularly; use technology to do other things together, like play games online - this is a creative and fun exercise that can promote bonding. "Loneliness will happen but it is important that you acknowledge and attempt to alleviate those feelings. Phone sex works wonders!"