First, read the English article below.

Thinning shears are often used by stylists in salons, and look like scissors with a thick, serrated edge. They are designed to cut about 15% of the hair, resulting in hair that still holds its shape and style but has less volume and density. You can buy the shears from beauty supply stores or the hair care section of most department stores. Before thinning your hair, shampoo and dry it as normal. If you tend to let your hair air dry, do that; if you use a blow dryer, go ahead and style it that way. Your hair should be as close to its normal, everyday texture as possible. This prevents you from over-thinning your hair. Don't add any styling products to your hair before thinning it. These can clog the shears and change how full your hair looks, which will affect your ability to thin it properly. It's best to thin a section at a time, and thin the same amount all around your head. Hold the first section away from your head and clip the rest back, focusing on just the ends of the section that you have. If your hair is shorter, you might have fewer sections because it’s difficult to thin hair that is close to the scalp. Place the scissors with the serrated edge facing down about 2–3 inches (5.1–7.6 cm) from the end of your hair, and position the shears at a 45-degree angle. Then, close the shears over your hair and open them. Move them down 1 inch (2.5 cm), closing them over the hair again. Repeat until you reach the bottom of your hair.  If you face the serrated edge down, then the hair will be thinner underneath, but it'll be hidden by longer pieces of hair. Be careful about starting too close to the roots. The thinning shears are actually cutting pieces of your hair, so if you start too high you'll end up with short pieces toward the top of your head. It's best to start thinning at the bottom of your hair to control the shape. Run a comb through a few times to remove all the cut pieces of hair. Then, take a look at the newly thinned section. Compare the section to the rest of your hair to see if you’ve thinned... 

Now, please write a short abstract for it in Vietnamese. Abstract:
Mua kéo tỉa mỏng tóc. Tỉa tóc khi tóc khô và sạch. Tách một phần tóc rộng khoảng 5-7,5 cm để tỉa. Dùng kéo tỉa mỏng tóc để cắt xuống thân tóc. Chải phần tóc đã tỉa. Tiếp tục thực hiện cho phần tóc còn lại.