Connect two well-known metaphors that are loosely related such as combining "It's not rocket science" and "it's not brain surgery" to create "It's not rocket surgery." This is the basis for all good mixed metaphors.
Begin spreading word of greatness by screaming your head off the rooftops. Good news is worth passing on, such as someone knocking the socks off the ball or pulling my legs over my eyes. No great feat goes unpunished after all.
Liven up a good sports conversation by letting the opposing team know you'll tackle that bridge when you get to it. Cheer on the underdog and hope they can keep the Cinderella slipper alive.
Warn others of their follies by letting them know they are skating on hot ice or wasting their time beating a dead horse to water. Rattle a few feathers by threatening to open a whole barrel of monkeys if necessary.
Use caution when using these methods or you may find people running around like chickens with their legs cut off. Err on the side of the train tracks when working a tough conversation but always remember that once you butter your bread you have to lay in it.
Wait for the right time, patience is required to mix the right metaphor. Practice on family before moving onto outside crowds, but with a little effort you'll soon be firing from the seat of your pants.