Teaching online is for the intrepid, for those who are not afraid of technology in all its glories and pitfalls. Leaning online, too, presents challenges and anxieties, as well as anonymity and flexibility.
One of the biggest challenges we face as instructors is Time Management -- or how to keep an online class from becoming a 24/7 class.
While in a face-to-face classroom, we, as instructors can easily see whether or not students are engaged, bored, comprehending or puzzled, online there is little to guide us on the day-to-day student response. Whereas face-to-face, we unconsciously reword sentences, rephrase lectures, repeat instruction etc. until were certain everyone understands, online we don't have those visual markers. As a result, most of us spend inordinate amounts of time online, and allow students to make inappropriate demands on our time. So what do we do about it? Here are a few suggestions that might help:
1. Make sure your lectures are clear and concise. Long stretches of text are difficult to read online, and encourage skimming. If you teach a course that requires lengthy reading materials, choose a good textbook, and assign students chapters from it. Then post Discussion areas with specific and directed questions. As well as responses, ask your students to post one or two questions on the selected reading. This will give you an indication of what they're not comprehending. You can then post a brief lecture on that topic.
You might also want to make your lectures more interesting visually, by inserting appropriate graphics. Above, for example, you'll see a texbook I use for 1st Year Creative Writing.
2. Create clear boundaries. You wouldn't allow students to come to your home to question you at any time of day or night. It's inappropriate to encourage them to do so online (unless you're teaching an intensive weekend course in which the parameters include 24/7 responses). Most university instructors keep regular office hours during which they see students. Create weekly online hours during which students can contact you through email or a Chat feature. You can also encourage them to email you during those hours with a phone number, if they want a personal phone call.
Creating boundaries means also letting students know that you won't be online day and night, and that you won't be online during evenings, weekends or holidays (in other words, choose similar hours to ones you'd keep if you were going into your office at work). I usually say that I pick up my email daily, and will respond within 24 hours (in the same way as I respond to my phone messages), but I do not pick up email from Thursday afternoon until Monday morning (here, you choose the hours, remembering that you need a personal life too, and that no one on his/her deathbed ever wished to have spent more hours at the office). 
3. Prepare your course in advance. Online teaching requires good organization you should plan the entire course in advance so that you are certain to cover the necessary material, and so that you have enough space to include extra lectures as needed. (Remember that you can hide your assignments so that students see only the current ones.) Also, it helps if you decide on a structure to follow each week or each unit (whatever you use to define a time period). For example, you might include a Book reading, a Journal exercise, an Assignment and a Discussion.
These are only three suggestions to help you manage your time when taking on online teaching. It's a rewarding, interesting experience, and I hope you'll enjoy it as much as I do.
Here is a link to an online resource you may find interesting. It's a book entitled, How People Learn. You can read it for free here: