Dogs steal food for obvious reasons.  The problem is easily managed by keeping food items out of reach.  Stealing other items, however, is a more complex problem and requires more extensive investigation before correction is attempted.

Your Food

Stealing food is simply eating that which is appealing.  In most problem cases, the pet has been given food items in certain situations, and expected to ignore the same food at other times, or a naive dog has the opportunity to take food when the owner is not present.  The simplest approach to correcting a food stealing problem is the realistic approach.  This requires that the owner take special and basically sensible measures to deprive the pet of the opportunity to steal food.  It also avoids the need for punishment or the more sophisticated and time consuming methods used with puppies. 

The puppy training methods may be tried if the owner wants to make the sacrifice, but only in conjunction with the standard rule, "Never leave food within the dog's reach." 

Your Personal Belongings

When various other items, such as shoes, clothing, and hairbrushes are stolen, the dog is usually displaying a lack of respect for the owner's leadership (particularly when stealing occurs in the owner's presence), or the dog has learned that its actions instigate an enjoyable ritual, such as a tug-o'-war.  These motivations differ somewhat from those of a dog that takes the owner's articles and chews them when alone or when it feels excluded from social activities.

When a lack of leadership and/or tug-o'-war are central to the problem, the pet must be taught simple command responses without punishment so as to reestablish the owner's authority.  All fondling of the pet must cease, as well as tug-o'-war and other orally stimulating interaction between owner and dog.  As in the case of food stealing, any items likely to be stolen should be kept out of reach.  If the dog is caught trying to steal something, the dog should be given commands to Come, Sit and Stay, and praised lavishly for its responses.

The firm "get away from that" warning also helps if followed by praise for positive response away from the item.  Yet another technique is to introduce the preamble to some kind of treatment the dog finds obnoxious, such as get out the nail clippers as the dog looks at the food, quickly go and start to run the bath water, get a tissue as if preparing to clean the dog's eyes, etc.