Get some chicken bones from your local butcher or save and freeze them when you de-bone chicken breasts. 

From Sean's Family Recipes
 
 

Prepare a mirepoix (chopped carrots, onions or shallots, celery or celery root (preferable, also known as celeriac) and garlic) exact quantities depend on the volume of stock you are making and your own
personal taste. 

Sweat the mirepoix on medium head with a little oil (let the veggies cook alone for a while).

If using fresh bones , add them to the mirepoix and heat them up. 
Do not do this for frozen bones and meat as too much blood will be released later and cloud the stock. 

When the bones are hot, add very cold water (as much as you want, depends on how much bones you have). 

Add a few peppercorns and whatever other herb and spice you like
(oregano is nice).

Simmer for 3-4 hours removing scum frequently. 

Strain stock through a couple layers of cheesecloth