Sure thing Screwballs – just let me know what airport, what runway to approach and what runway to land after circle, "existing" weather conditions, and, if you have access, an appropriate approach plate. If you don’t have one, I may be able to come up with one. I’ll await your information.
A theoretical, sea level airport. 09/27 4000m nil slope dry runway. ILS on 09. Minima for Cat C. Company minima 1,000ft AMSL. Actual weather 10km visibility. Cloud base is minima plus 200ft(1,200ft). Nil significant weather. Wind is only 270/10. ATC request you circle to land on 27. Nil terrain issue, MSA in all sectors 1,100ft. Temperature 15. QNH 1013.25. Boeing 737-700 at a nominal weight. Approach speed 140. It's 1224Z on the 17th of February. 2012. You are on the prime meridian. The sun is up. If I haven't mentioned it, it isn't there.
So back once again to the original query: how do you describe the circle to land, specifically the downwind leg and turn from there through base to final?