Here is a good FAO document on ridge and furrow cultivation and
planting. The emphasis is on furrows for irrigation, but the principles
of how to shape the furrows and where exactly to plant on the ridges
would be useful where the furrows primarily provide rainfall runoff,
too. (You want your ridges and furrows to run downslope, even if it
is only a very slight grade.)
http://www.fao.org/docrep/S8684E/s8684e04.htm
(Once your soil has been improved with organic matter for a few
years, maybe you want to change your method. I am imagining
"year one" here, how to get a garden to work in heavy clay soil
without bringing in heavy equipment to break it up and amend it
or a lot of materials to build raised beds.)