1. Start in your comfort zone.
Consider how you provide 'substantive' contact to your face-to-face (f2f) students. Do you enjoy facilitating class discussions? Do you prefer one-on-one meetings where you provide feedback? Do you have journal assignments where you communicate with your students through extensive feedback on their journal comments? Do you have a hands-off approach to discussions because you want the students to direct the conversation, but then offer concluding remarks and a discussion summary highlighting the key takeaways? Whatever you already do, start with that and just apply it to the online experience. Once you are comfortable with those familiar methods, you can expand your modes of 'regular and substantive contact'.
2. Know your students, content and technology tools.
See what methods fit best with your students and content area, and can be accomplished using technology you have at your disposal.