Just take a newish stem off the bush . Cut off below a leaf axil, after stripping off leaves from 1/2 way along the stem. Dip in rooting powder, if you have any. Use suitable compost and poke them in. Set aside and keep watered. check for rooting by gentle pull, if the cutting feels firm they are getting anchored. Protect from frost. Best time is probably when there is active growth. A plastic bag over the pot held up by a stick helps too.

As above but I would suggest using a mix of 3 parts potting compost to 1 part horticultural sand. I take hundreds of fuchsia cuttings a year on my plant nursery and find the best time is when they are in full growth from early July to late august. Keep them damp but not soaking wet in a shady spot or preferably in a shaded coldframe. They will root in 3-5 weeks. Non hardy fuchsias must be given heat over winter but I bring my hardy fuchsia cutting indoors for th winter as I find they're not totally hardy in mid latitude UK until year two when the stems are tougher.

There's more information on cuttings on my Flickr pages

http://www.flickr.com/photos/31559373@N00/725769578/in/set-72157600840587482/