Pick a neutral hair color that's close to your natural shade. Don't go crazy with the whole hair dyeing idea; the goal's to blend the grays, not cover your hair in a whole new color. Use color swatches to determine which color closely matches your own or if you are buying your hair coloring kit from a drug store compare the before color to your natural shade.
Use a semi-permanent color or a demi-permanent color with no higher than a 10 volume developer if your hair is less than 25 percent gray. Anything higher and you'll risk lifting or altering your natural color when all you really want to do is blend your grays into it.
Divide clean but dry hair into sections, so that you have two in front and two in back. Clip each section in place with a plastic hair clip.
Apply a skin protector around your hairline -- think petroleum jelly -- so your protected against colorful stains on your skin caused by dripping dye.
Glove up and mix your hair color if using a demi-permanent. If using a semi-permanent color chances are there's no mixing required, but if the directions say its required go ahead and follow with the mixing.
Start applying the color to the section of your hair where you're seeing the highest concentration of those annoying gray hairs. Once you've completely applied it to one section, unclip and start another until all four sections are covered in dye.
Find someplace cozy to wait it out and process your hair for the instructed amount of time. Just don't settle down in a drafty location or someplace where your furniture will get a dye job as well.
Rinse the color from your hair after it has processed using warm water. Completely rinse until all of the color is gone and the water runs clear.
Condition your hair with the conditioner that comes with your hair color or with your regular conditioner if you are not using a coloring kit.
Towel blot your locks after rinsing your conditioner out with cool water. Check your hair to verify that the gray has been successfully blended.