Select a fairly thin cut. 

Blot any moisture off the outside; water is the enemy of a good sear.

Leave at the very least 1/4 inch of room between pieces in your pan; overcrowding promotes steaming, another enemy of a good sear.

A well-seasoned cast iron pan is a good sear's best friend; put it over high heat with a couple tablespoons of oil. When the oil just begins to smoke, add your meat.

Let it cook undisturbed for a proper browning; it will stick when it first hits the pan, but will release after the crust forms.

After your food is seared on both sides and removed to a platter, take advantage of all those tasty bits (called fond) in the bottom or the pan. Add a splash of wine or stock and scrape them up and make a pan sauce.