Military deception is the antithesis of camouflage. Camouflage is designed to hide you, make the enemy think that you aren't where you are. Deception is the opposite, making the enemy think you are (or something) is somewhere that you are not.
Deception falls into the realm of "Information Warfare" and the common tools of deception are: decoys, false positions, false intelligence/signals, sensor spoofing, pattern conditioning, feints.
Think of every platform your enemy will be drawing intelligence from, and those are your opportunities to deceive.
Decoys: These are the basics of deception. A false minefield will have the same effect slowing the enemy as a real minefield for a while, an unmanned aerial drone may cause the ground forces to switch on the SAM Radar to target it (and therefor make it a target for a HARM strike). Remember, if a camouflaged position says "Nothing to see here!" a decoy needs to say "I'm a legitimate threat!"
False Positions: In the days of old, armies would increase or decrease the number of cookfires in the camp knowing that enemy scouts would report the number to the enemy general. In modern warfare this can be fighting positions with broomsticks sticking out, as long as it looks "real enough" to cause the enemy to fight you where you aren't, or underestimate (or overestimate) your strength.
False Intelligence/Signals: Assume everything you push out over any communication channel will be compromised. In WWII the Allies dropped a cadaver dressed in an Allied uniform with false plans in an envelope inside an attache case into the sea where a German warship could recover it. To ensure that the false battle plans were gauged by the enemy to be real, radio communications were sent out to reinforce the false intelligence. By reinforcing a falsehood German troops were not in place to respond well to OPERATION OVERLORD.
Sensor Spoofing: In WWII to support OPERATION OVERLORD the allies spoofed German Radar sights looking at the English Channel by having aircraft fly orbits over the water and drop chaff. This caused a massive return on the German Radar Screens that looked like the invasion of Calais that the Germans expected from the false plans and false signals recieved.
Pattern Conditioning: This is where you don't aim to spoof anything but your opponents expectations. Your patrol moves out every night at 2100 and returns every morning at 0500. You do this for a week straight with a single squad. Except the next week you do it with 3 extra members of the platoon, and leave them behind at a fighting position of your choosing. Now you have 21 members of your Platoon moved across the battlefield into a position where the enemy does not expect.
Feints: A military feint is when you attack deliberately where you think the enemy will expect your main attack with something to draw the bulk of his forces away from other areas that you really want to hammer. You do this by plussing up the Feint operation to look like the main attack. One thing I learned as a very young soldier is that you NEVER abandon your post to go where the fighting is on a defense, if the defenses need to be arranged you must let the leadership do their job and rearrange it, because the moment you abandon you post to help your friends you create a gap in the defenses that a smart enemy will exploit.
And there you have it, a criminally brief introduction to the shaping operation known as military deception. The bigger the operation, the more intensive the deception plan needs to be. In 2003 GEN Franks left the entire 4th Infantry Division bobbing on boats in the Med to support a deception plan created by feeding false intelligence to an Iraqi spy about Jordan opening a western front for the Americans. And it worked. As Patton is alleged to say, "A battle plan without a deception plan isn't a plan."