Mercerization is a dangerous process, and therefore not suitable for anyone without laboratory safety training. You would need to wear goggles or preferably a full face mask (similar in shape to what welders wear), long chemical-resistant gloves, lab coat, and a long chemical-resistant waterproof apron. 

Here's a recipe to consider: stretch fabric or yarn tightly on some sort of frame, soak it in a room-temperature bath of 20% sodium hydroxide for five minutes, then rinse, neutralize the pH with dilute vinegar or citric acid dissolved in water, and rinse some more. To make the sodium hydroxide bath, you would slowly add 200 grams of sodium hyroxide to something like 700 ml of cold water, then top it up to exactly one liter. 

Sodium hydroxide is also known as lye or caustic soda, and can cause severe burns. A small splash into your eyes can cause blindness. If you get sodium hydroxide in your eye, you must hold your eye open while flushing it with running water for at least fifteen minutes, and then seek medical treatment. When dissolving sodium hydroxide, add the crystals to water, never water to the crystals. A considerable amount of heat will be generated. 

Stretching your fabric or yarn before mercerizing is necessary in order to prevent shrinkage and to produce the desired sheen; if you don't stretch it, the process is called slack mercerization, and will result in significant shrinkage and will not increase the sheen of the cotton. It will improve the color intensity obtained by dyeing the fabric or yarn, however.

Doug Wilson and Olli Niemitalo posted about mercerization on the DyersLIST some time ago, so look in that mailing list's archives.

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