I don't know much about how to enter into a relationship online; I know people who have done it, but it's never been something that I've been interested in. However, many of my strongest friendships were made online.
The trick to making friends online is to not set out with the intention of making friends. It's paradoxical, I know. What you should do is just find something that you're interested in, find places online you can talk about them, and try talking about them. Personally I like math, so I met some friends on internet math chatrooms and forums. I like Star Wars, and I made some good friends through talking about Star Wars online.
Many such places also have a casual conversation place attached. In niche communities where you (a) are already engaging with people with a common interest and (b) there's few enough people that you will see names and faces regularly, but enough people that the conversation never dies down, eventually you'll become a known quantity and make friends.