Wash and condition your extensions with a volumizing shampoo and conditioner. Any shampoo and conditioner you would use on your regular hair will work fine on your extensions, just make sure the products you choose are listed as moisturizing and preferably, of a reputable brand name in the hair care industry, such as Redken or John Freida. You need to treat your hair extensions like your regular hair; if you want to volumize your extensions, you need to use the right products.
Attach one hair extension piece--which is known in the world of professional hairstyling as a weft--to the side of a piece of cardboard. Place the cardboard onto a ledge and sit a door stopper or other heavy item on top of it to keep it in place. This is going to let you keep your hands free and make it much easier to style your extensions.
Blow dry the hair on the extension with a round brush. Roll the brush on the underside of the hair, moving in a downward motion; focus the air from the blow dryer towards the brush as you go. Although most hairstylists and in particular extensions specialists recommend allowing your extensions to air-dry after washing, if you want to volumize your extensions, this is the best way to do it. As you blow dry, you should see body and volume building up in the hair. Repeat this on the rest of your extensions.
Section your hair with your fingers, creating a part spanning from the bottom of one ear to the other, and attach the first hair extension on the hair just below this part. Let down another section of hair and attach your next extension in the same manner, continuing in this pattern until you have attached all pieces. It can take a bit of practice to get used to it; after that, inserting your hair extensions will be as easy as updating your Twitter status.
Working in one-inch to two-inch sections at a time, clamp a hair straightener around the top of a section of hair. Lift it up and out, moving the hair in a sort of "C" shape, and then follow through down the length of the hair and over the ends. Straightening the hair in this manner lifts hair at the roots and gives you that super sexy and voluminous Jessica Rabbit-style locks. Spritz hair with a bit of light hairspray, to finish the look and help your hair from falling flat. Work it!
If you use heat styling tools on your hair, make sure you take proper care of your extensions in order to keep them in the best condition. Wash and condition them regularly; apply a deep conditioning treatment--such as a hot oil treatment--at least every one or two months.
Spray a heat protectant onto hair before blow drying, to help protect the hair from damage caused by heat.
Blow drying your extensions too frequently is not recommended. Heat styling causes damage to the hair, and extensions do not receive natural oils as your regular hair does.