Step1
Once you know the preferred religious or secular format for the handfasting ritual, research online or in a library. This handfasting is mostly laid out for pagans, but it can be adapted.
Step2
If not already done, write a basic Circle calling ritual. For most modern day pagans, this should cast the Circle and invoke the Quarters. A good circle size is about nine feet, and the Quarters are North, East, South, and West. Please adapt Quarter calling to couple's specific religion, each branch of paganism has its own idea of the manifestation of the Quarters.
Step3
About a month before the handfasting ritual, start discussing with the couple the features they would like to emphasize, and make sure all supplies are available. Supplies include but are not limited to: altar table, altar cloth, altar statuary, incense, handfasting cords, athame, wand.
Step4
Also discuss with the couple how they would like their vows done. Do they want you to demand a specific oath of them to which they can reply "I do"? Or do they want to write their own vows? Write full ritual to take preferences into account. Feel free to get poetical.
Step5
On the date and time of the happy occasion, cast the Circle, invoke the Quarters, and ask the blessings of any pertinent god/desses on the sacred space. Ask by name for each person to step forward if and only if of pure heart and true intent. Follow agreed upon script for vows. Ask divinities to witness and bless those vows, thank them for their attention, and invite them to the party.
Step6
Thank the Quarters for their attention and blessings, and let them also know that while they are no longer needed, they are also invited to the party.
Step7
"So it is spoken, the Circle goes unbroken. Let all be released from this sacred space, and to all Blessed Be." Or something with that general idea in mind. You don't want to break the Circle, you want to release it. Now, yea verily, go and party.
Authority 
Comments
FoxtailsLaundry said
on 5/13/2008 Well, I've come across several ideas for tying the cords. One of the easiest is to fold the cords in half, wrap around the couple's wrists, put the two ends together through the loop of the fold, and pull taut to comfort level for the duration of the ceremony. At no time should you tie two people together in such a way that they cannot get apart in an emergency, so no complicated knots that take forever to get apart. In addition, large round cord is a better idea than thin, flat ribbon for safety reasons. If you're going to use flat ribbon, it's better to just loop it over prettily and don't even think about a knot. After all, it's the symbology of the thing. ;)
ErnestCT said
on 5/1/2008 Thank you, Loni, for very _practical_ advice! You've covered about everything except the actual tying of the ribbons / cords. Would you please add a little about the pattern? Thanks!
zaradei said
on 10/20/2007 Very interesting!
FoxtailsLaundry said
on 10/11/2007 Sorry, nine foot radius. Take a stake and a nine foot cord, put stake in middle of circle and walk with the end of the cord in your hand. It comfortably fits quite a few people. Nine feet in diameter wouldn't fit all that many.
Nyko said
on 10/9/2007 thank you for writing this