An important other thing to consider -

You need to "break-in" your new clipless pedals. They can be maddeningly difficult to clip correctly when they're really stiff and new.

I use the high-quality Ultegra-SL pedals. When I first got them, I was nearly unable to clip in to either side unless I put all my body weight on it dead on, and even then, it only worked 50% of the time. I loosened the tensioner and it still didn't help. My friend advised me to break it in, and I spent a good 20 minutes just clipping in and out like crazy while on the trainer.

Sure enough, that helped a lot. Now, a year later, it clips in like butter. I just put my foot down and it clicks right in.

Break those suckers in - it can make a big difference.