I had the same problem
Bluetree, you are not alone in having problems with the Keos. When I bought my road bike, I had the Keos installed immediately (I had previously been riding a hybrid with SPD one-sided pedals). The adjustment to the Keos was a little rough. In fact, I almost gave up after the first ride. I, too, had trouble getting through tricky intersections and/or inclined intersections without losing my you-know-what. I assumed that the Keos had design flaw but my LBS assured me that they were purposedly designed to float backwards like that. After a few months of using them, though, it's gotten a lot better. Here are some thoughts/suggestions (and sorry if I'm repeating what others have said):
First, make sure that the tension on the pedals is pretty loose so that it's pretty easy for you to clip in and out. There are instructions on the box about how to do this.
Second, before hitting the roads again, practice in a parking lot or grassy area. Stop and start over and over again. As you start rolling, try to clip in without looking down at the pedal if you can.
Once you're on the road, make sure that you downshift (if you're not already in a lowish gear) before coming to an intersection so that you can get rolling again pretty easily. As you're waiting for the light to change, rotate your pedal so that your clipped-in foot is in the three o'clock position. When the light changes, really concentrate on pushing down hard with that leg so that you can start rolling--using all your body weight as you hoist yourself back in the saddle.
As the other pedal rotates forward, rest your unclipped-in foot lightly on top of the pedal so that you can rotate the pedal to get through the intersection. Don't worry at this point about clipping in. Once you're safely through the intersection, finally clip in.
Sometimes I still have to look down at my left pedal to get clipped in, but it has become much, much easier to get clipped in w/o really thinking about it. When I come to an intersection with an incline, I still panic a bit to be honest. There's one intersection in particular where I try to crest the incline before stopping. Otherwise, I hang back from the intersection a bit (where the road is a little flatter) and start off from there when the light turns green.
One other thing: After riding for about six weeks with the Keos, I had a professional bike fitting. I mentioned my problem with the pedals to the fitter and he told me that one of the reasons that I was having a hard time clipping in is that my saddle was too far forward--meaning that my knee was falling too far in front of the pedal axle. As he predicted, by moving my saddle back, it became easier for me to use the pedals, presumably because the angle at which my toe approached the pedal to float it forward was "better." You might want to make sure that your saddle is in the right fore/aft position, too.
Keep at it; it will get easier. Good luck.
Kate
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher