friend of mine had a very same problem and I was trying to help him...
What I've noticed is that he was trying to push his foot down using the leg muscles. I suggested he use his weight instead and after few attempts he was fine.
So, try engaging the pedal at it's 4-5 o'clock point and lift your other leg up so your total body weight is supported only by the leg that you are trying to engage in pedal... slight twist, like you are trying to extinguish a cigarette butt, and that's it
As patently obvious this advice may have sounded, it seems to have done the trick!
I moved the crank up to the 3 o'clock position, and then pressed down with my body weight while wiggling my foot, and by the time the crank hits the 6 o'clock position, it's clicked in. The thing I need to practice is regaining stability after putting all my weight to one side (since with Look pedals, my leg muscles seemed to do the trick without having to shift my weight to one side.)
Thanks for the help everyone!