Before I put on the first coat of drywall compound, I used some fiberglass mesh tape to cover any cracks in the plaster. The tape combined with the strong setting-type drywall compound will help prevent the cracks from reappearing in the future.
After taping the cracks I put up the first thin coat of "hot mud". It's a plaster-of-paris based mixture that sets chemically into a relatively hard layer. Tomorrow I will do the first topcoat using a regular light topping compound, to be followed by one last topcoat later this week. If all goes well I'll be putting up moulding within a week or two.
Lesson Learned: Clean the walls first!!! I usually go over the walls with the edge of a 6" drywall knife to knock off any cling-ons leftover from the wallpaper. I obviously forgot. Don't make the same mistake! It's very frustrating to be putting on a beautifully flat, thin coat of mud, only to have a gouge running down the middle. Argh!