When I ride recumbent it's on a Bacchetta Cafe (2 wheel, above seat steering). I like riding witout my feet attached to the pedals, and use the placement of my foot on the pedal similar to shifting gears. This helps mostly with climbing hills since we can't stand on the pedals to use our weight. On flats or downhill I place the axis of the pedal across the top of my arch or ball of my foot. Going uphill I place the pedal axis across the middle of my arch to lower arch. The lower you go, the more direct (from leg) power you give the stroke (less utilization of the heel muscle). Note this effects x-seam lengths, and the technique should only be used when you are at less than your maximum extention, otherwise you'll feel the effects of overextension in your lower knees. Or at least that's what I've found.

In terms of getting adjusted to riding a recumbent for the first time, if you have above seat steering the difference in how you apply pressure to your handlebars (from upright bike) can take a bit of getting used to. I suggest when on a flat straight run, lift the handlebars slightly, so that there's no pulling pressure, and notice the difference between that and how they react when your natural arm weight sets on them. I find that I was so used to continually applying a "pushing" pressure to the handlebars, that I wasn't noticing the subtle differences that "pulling" (towards you) created. Also, remind yourself, that you can't steer by shifting your body weight. Those are the two main things I learned in the 50 miles it took me to adjust to a recumbent, and imagine that if it had been pointed out to me on the front end, I might have adjusted a little more quickly.

Oh, and think ahead about downshifting for stops, etc. Your doomed everytime you come to an unanticipated stop in too high a gear since you can't just stand on the pedals.