Some years ago when I went to one of my Anchorage Weaving Spinning Guild meetings there was a class that was being given on mordanting your wool before dyeing it.  Being a beginning dyer I didn't know what that meant but I soon learned that it would help with plant dyeing or doing any other kind of dying.  As it would enhance, intensify or change the color of the dyebath and make the colors more a shade lighter or darker and more  fast to light and to washing.

Anyway's I thought that I'd post here what I learned steps wise that day when mordanting for the first time.  Thought it might be of help to someone else.

1. Always use a plastic spoon when measuring your mordants, and use glass or plastic cups to dissolve the mordants in. (never use dyeing equipment for food collection, storage or prepartion.  Keep all your equipment out of the reach of your children and pets).
2. Dissolve your powdered mordants thoroughly in boiling water, and dilute the  liquid mordants. 
3. touroughly wet the fibre to be mordanted.  If your going to mordant handspun yarns, carded wool, cotton, or silk you will want to soak them overnight.  This will expand the fibres which will ensure more even penetration of the mordant or dye.
4. Add the dissolved mordant to several gallons of lukewarm water in your mordant pot.  Then place your wet fiber or yarn in the pot, making sure there is enough water to cover it completely.  Your fiber or yarn should be able to move freely in the mordant bath.  Never pour your mordant mixture directly over your fiber or yarn in the pot.  As it will cause your dyes to become spotted later.
5. Don't stir your yarn or fiber about in the pot or push it down against the bottom where the water is the hottest.  As stirring will cause the fibre or yarn to shrink and felt, and pushing it to the bottom will result in streaky mordanting and streaky dyeing.  Instead you will want to gently lift the yarn or wool and turn it over in the pot doing this from time to time so that no certain part of your yarn or fiber  is exposed to the bottom of the pot for any length of time.
6. You will want to start with lukewarm water in the mordant bath, and gradually raise the temperature to a simmer (200 F, 95 C) over an hour.  Once the water reaches a simmer, time your bath for an additional 30 to 45 minutes.  You can leave your mordanted yarn or fiber overnight, which will result in extra fastness and usually a stronger, deeper color.  However, if you are going to leave your yarn or fiber to continue mordanting overnight you need to remove it from your pot and put it into a plastic bucket.  First remove your yarn or fiber and pour your mordant into the plastic bucket then return your yarn or fiber to the mordant bath.
7. After mordanting, your fiber or yarn needs to be rinsed in successive baths of very hot, then cooler water.  The first rinse should be in water that is the same temperature as the mordant bath.
8. After rinsing, allow your fiber or yarn to drip from a plastic or stainless steel colander.  Don't wring wet fiber or yarn, or even twist it to remove the excess moisture.  Instead gently squeeze the water out with your hands. 
9. Usually after mordanting you will want to dye it right away or dry it thoroughly for future dying use.  Wet mordanted fiber or yarn can be stored for a few days in a plastic bag, but I don't recommend doing this.