Select your spoon. Don't use expensive silverware; in fact, older spoons might be easier to bend.
Prepare the spoon. Bend the spoon back and forth many times until you can feel that the metal has become softer. Bend it at the point where the handle joins the scoop. This step may not be necessary for some spoons.
Present the spoon to you audience. Tell them that it is solid and unbent. They're likely to believe you, particularly if they can see that it appears to be so. Tapping it on a table or other solid object makes the suggestion even more powerful.
Set the mood. Pretend to concentrate heavily, and to summon your supernatural powers. Utter appropriate patter in an appropriately mystical tone of voice.
Create a distraction. As you grasp the spoon in one hand, draw attention to the other hand by waving it, or to your face by bringing your hand to your face or just closing your eyes. Utter magic words or appeals to cosmic forces to assist you.
Bend the spoon. Do it quickly and unobtrusively, at the precise moment your distraction starts. It isn't hard, especially if you use your thumb.
Distract with motion. Holding the spoon at about the point where it bends, with the back or front (but not the sides) facing the audience, shake it back and forth (toward the audience and back) with wrist motion. As you do this, work your hand down the handle so the spoon appears to be growing longer and bending before the audience's eyes.