Be sure to brush your dog before any bathing takes place. You will want to remove any mats beforehand. Wet mats only become more tightly wound and may have to be clipped out by a professional
Cover the bottom of the bathing area with a non-slip surface such as a bath mat. Make sure the shampoo you have selected is right for your dog's coat. There are shampoos that are meant for white dogs, soothing ones for dry skin, flea baths, and conditioners for dry coats, too. Make sure to read the label for any dilution recommendations.
If you are already using a spot-on flea product, avoid flea shampoos. Make sure your flea protection doesn't wash out with shampoo. Check the label to be sure. You may need to re-apply after the bath, once the coat is dry.
Start with tepid (not hot!) water and work your way from the head back towards the tail. Use a sprayer so the water penetrates all the way to the skin. Break out the shampoo and work up a good lather. Avoid eyes and inside ears to minimize irritation. Follow label directions for how long to let it sit on your dog's coat.
Towel-drying is a good start, but longer or thicker haired dogs will require more. A hair dryer on a cool setting will work, or if it's a nice day, a little time in the sun. Beware that if outside, your pup will instinctively roll around in the grass, and that may undo all your efforts. A little time in the crate on a towel can work just fine.