When it is time to give your dog a bath, be sure to assemble everything you will need prior to putting your dog in the tub.  The last thing you need is to end up chasing a wet, soapy, slippery dog through the house.
Some of the things to remember are: your dog's brush and comb, dog shampoo, pre-mixed vinegar rinse (if you use it), and plenty of towels within reach.  [The vinegar rinse does a great job of cutting the shampoo, reduces rinse time, and relieves the itching and scratching.  However, when using the vinegar rinse, you must be careful not to pour it over your dog's head, especially not in the eyes; and your dog will smell like vinegar afterwards.  The vinegar rinse is made by combining 1(one) cup of vinegar and 1(one) gallon of water.  Do not use vinegar straight.  It must be diluted.]
    Should you own a dog that has wrinkles, such as a pug, bull dog, bloodhound, French bull dog, etc., be sure to have baby wipes on hand to clean the wrinkles.  You wouldn't believe the amount of food, dirt, moisture and bacteria that can get trapped inside these wrinkles, and can be a source of "that doggie smell" at the least, and a massive infection at worse.
    Most professionals start the shampooing process at the neck.  If you're using flea shampoo, get the neck area lathered up before wetting down the rest of the dog.  The fleas will try to hide in the eyes and ears when they think they need to run for cover, so just block off that route to the head area first.
    Once you've worked the shampoo into a good lather, use your dog's brush or comb to work it through the coat.  There's no need to be rough, just brush in the direction the hair lies.  This will also reduce tangles.
    You can rinse your dog thoroughly by running the water over the dog until the water runs clear, your dog's hair will squeek when thoroughly clean.  If you notice that your dog is scratching after a bath, it's probably because there is still soap residue left within the dog's coat.  You can take a cup of vinegar and dilute it in a gallon of water, pour this over your dog (not the head, please), and then rinse thoroughly.  You will discover the vinegar solution "cuts" the shampoo, reduces rinse time, and relieves the itching and scratching.  The drawback is your dog does have a vinegary smell.
    The drier you can get your dog the better, some dogs enjoy being wrapped up in a towel for a few minutes, others just love to shake that water all over.  After towel drying, you do have th option of blow drying the coat.  If you have a long haired dog, you may just want to keep combing until the coat is dry to keep mats and tangles from forming.

CAUTION: Any dog can have an allegic reaction to a product (flea shampoo, dips,etc.).  If you notice your dog is having trouble breathing and is salivating excessively, or goes unconscious, you have only a few minutes to rinse off the product and get your dog to a vet.
While transporting your dog keep him as warm as possible - he will be going into shock.