Identify what/who/where your dog guards.

Learn about canine body language and make a list of your dog's cues that say, "keep your distance!"

Securely hide commonly guarded & scavenged objects like socks, shoes, and paper products.

Tell friends and family to give Fido space when he is on his bed, has a bone, etc. Using an Xpen around that area can help as well.

Avoid areas outdoors where Fido may commonly find "treasures" he's not fond of parting with.

Start with less important objects/food/people and build a predictable routine. Ex., Ask for Sit, toy comes out, Fido waits, then toss it to him. 

Build your "I've got something BETTTER" rep with your dog by always having something really yummy in situations when Fido typically guards.

Be generous! If Fido drops or moves away from a guarded object, pay him $$$ with delicious treats.

If your dog guards a person or location, have people walk by with enough distance to prevent the guarding behaviors and drop yummy treats.