Use Eyebrow Pencil:
If you are planning to darken your brows use an eyebrow pencil. You will find this as the most convenient method to colour your eyebrows. Select a colour of eyebrow pencil that matches with the colour of your hair and enjoy having the right eyebrows.
This is a temporary solution and you can have as many colors of eyebrows as you want with this method, as it doesn't have any side effect and you can do it easily at home too.
You may also use a powdered shadow along with a brush to brush the colour into your brows. Now set your eyebrows with a brow gel. Certain brow gels come with a feature of slightly colouring your brows in addition to setting them.
This is also a temporary solution and allows you to have a different eyebrow color each time you want!
Get Long Term Color with Hair Dye:
You may also use hair dye mostly if you are trying to lighten the colour of your brows to match the colour of your hair. You have to use it with great caution and care. For this, firstly, place a small amount of dye on a Q-tip and brush only onto the thickest area of your brows. Check it after every three minutes and remove with soap and water after you get the desired colour. Do not use it with bleach.
It's always good to have someone's assistance while doing this, else you might not be able to do it properly yourself.
Get it Done by a Professional:
Get the services of a professional colourist. Professionals are well-versed and know all the tricks of the colouring trade. They will not only colour your eyebrows but will also advice you for hair and eyebrow care.