It all depends on the style of the sofa and chair. Overstuffed do not slipcover well, JMO. However, the classic styles do. I used to cover furniture with my mom and the snugger the fit the better the cover laid. She also would put zippers down the side back seams of her slipcovers to make taking on and off easier. I would assume most patterns now a days would have that. Youtube would be a great source as well as your local library. Just takes patience.:)
http://www.google.com/search?q=youtu...ls=org.mozilla:en-US:official&client=firefox-a