I'm an expert on catching dropped soap in the shower and I'm always getting emails and phone calls from people asking for tips. Well, having superior natural abilities is important, such as lightning fast reflexes and a killer instinct, but the determining factor is generally technique. Most novice soap-catchers try to grab the soap from the top as it's falling, with one of two results: either the soap gets clubbed to the ground by the flailing hand, or the fingers actually do grasp the soap but fail to get a grip and the soap goes shooting out in some random direction. Fools!
The only way to reliably, safely catch falling soap is from below! Simply cup your hand and gently position it under the soap. The slippery devil will land gracefully in your fleshy bowl, and once you've arrested its momentum you can curl your fingers around it to maintain possession -- but only after the soap is securely nestled in your palm!