[Ibby]

What works well for pretty much every camo pattern and coloured fabric is as follows:

The first wash, add about a cup or so of plain white vinegar to the wash. (It's also good for removing the smell of sweat from clothes when they get older)

When you wash your stuff regularly:

turn it inside out.
wash it on cold.
use a gentle soap like Ivory, baby soaps, etc.
don't use soaps with phosphates.
liquid laundry soap is better than powder.
obviously, don't use bleach.
hang dry, then shove it in the dryer for a few minutes to get the wrinkles out if you need to.

The biggest thing that fades your colours is chlorine and minerals in the water. If you've got the green, put a water filter system on your washing machine hoses.