[thejokerswild]

You need to be a good liar. A lot of experience reading and predicting opponents reactions so you can exploit them. Put pressure on the opponant if you call his bluffs. Many rounds of sparring and practicing good technique. Most feints revolve around the jab, when you're shadow boxing you can practice setting up a feints by jerking your bodys movements into a punch without throwing, then add surprise punches.

Even if you train train train, the most unpredictable punches can come from wild fighters with little control, their strength is their weakness I guess so be careful trying to feint those guys.