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This is probably the fastest way to get longer hair! Go to a beauty supply store and pick out extensions that match your hair's color and texture. Clip them in under the top layer of hair, close to your scalp, so they'll blend in well.  Get enough clip-ins to evenly place around your hair, so one side doesn't look thicker than another. You can get clip-ins made from plastic, real human hair, and other substances. Keep in mind that synthetic clip-ins won’t blend well with your natural hair and they will not last for very long. The more you want to spend, the more realistic they'll look. This is a more expensive, more permanent version of extensions. Extensions made from real human hair or faux hair are woven, sewn, or glued to your hair or scalp. This is a popular method for getting instantly long hair used by celebrities.  It's extremely important to make sure you go to a salon technician who knows what he or she is doing. Do not get extensions or a weave done by an amateur. It can lead to pain, irritation, and hair loss. Only try  putting in your own extensions if you're extremely confident in your abilities! Otherwise, you might lose some hair in the process. Want instantly longer hair? Why not try a wig? You can experiment with all kinds of hair colors and textures, and best of all, you can make your hair as long as you want. Go to a wig store and talk with the representative there to help you pick out one that looks good with your coloring and facial features. You can even have your wig cut and styled at a salon if you want.

Summary:
Get clip-in extensions. Get a professional weave or extensions at a salon. Try a wig.