Good thinking Genghis, let me add my pennyworth:
(1) Establish best glide-angle speed and pick a field that I can reach, if the wind is strong, ideally into wind, if it isn't (or not clear) ideally up a gentle slope.
Why not pick an area of fields so that you can refine your choice as you get closer? Ideal fields are often surrounded by similar fields! If you can see a gentle slope from the air, it will be a marked slope on the ground! If you land uphill you invariably land in the undershoot.
(3) Imagine a runway starting at that aiming point, set myself up as efficiently as possible (a) ideally downwind, (b) if absolutely necessary on base, or (c) if I was very low, in which case I was flying field to field anyway, on finals.
Why restrict yourself to an imaginary runway, a large grass area is better as you can come at it from any direction thereby regulating the track distance.
If you fly constant aspect, you need to establish the ideal low key height for the aircraft type; that should place you downwind with the aiming point just aft of the wing tip.
(5) At 100-200ft ( a bit higher if a really big field), roll wings level, establish approach speed, and set up to land. If too high, sideslip, dive or S-turn the excess off, depending upon preference and type - but always aim to err on being slightly too high.
Try to roll out wings level on final by 400 feet, with no flap. Then take flap in stages lowering the nose to retain the glide speed whilst bring the aiming point towards you. Retain the glide speed untill you flare, initially to a normal approach attitude (that washes off the extra speed) then to a normal flare for landing.
If you fly a machine with retractable gear and a VP prop you need to establish the basic parameters before it happens for real, some need a lot of height at "low key".
Remember don't let the other pilot get you into a position where you can't get it into a field!