Create memories that will tide you over until the next time you're with each other. Send cards and emails. Perhaps create a personal website in which pictures are posted of what's happening in your individual lives, thus allowing your partner to share in some of the experiences. In a LDR, it's important to focus on what you have going for you and not what you're giving up in order to maintain the relationship. Let me add one more thing.
College is a very special and precious time in one's life.
It is a time to explore and expand one's life experiences. Have an honest, heart to heart talk. Weigh the relationship and examine the sacrifices that both of you will have to make in our to preserve the relationship. Several months ago I met this woman on the net who lived in another city. We first started writing.