here is one site on grounding and protection that describes it and gives an example of this.
http://www.rescuemediums.com/grounding-and-protection.php
I will say that I like to ground myself daily as soon as I get out of bed and any other time during the day that I think of it or feel I need to do it again. What I do is when I get out of bed every morning is to stand still for a few seconds and envision roots growing out of the bottom of my bare feet and going down through the floor boards into the ground like tree roots. Its one of the easiest ways to ground yourself and can be done anywhere.
Another good way of grounding when you are getting ready to do a reading, or immediately after a reading is to eat or drink something that comes from the ground or from an animal that is not a meat eater--such as milk, veggies, etc. even cheese is good! My favorite is a glass of milk, some cheese and crackers or instant mashed potatoes. (only because they are quick and easy to make).
As for protection, this is also very easy to do, and is explained in the above web site. Just envision a white or golden light coming down from above you and it slowly envelopes your head and proceeds to work down your face, neck, shoulders, torso, arms and legs and your feet. Imagine this light extends a few inches out from your body and its like you are inside an eggshell. simple to do!
I also have crystals that I use too when I am doing a reading, or going someplace and feel I need some extra help to keep me protected and at ease. Just being near these crystals is enough. Plus, I wear a few crystals on a necklace and the Catholic girl in me insists on also wearing a Miraculous Medal and carrying my rosary in my pocket. But the last two are things that I've done pretty much all my life--so its more habit then anything else.
I have found that sometimes when I read for a customer and have taken on a lot of their energy--or if I've been around any psychic vampires--a shower really, really helps me too! I take a nice warm shower and I love to feel the water just coming down onto the top of my head and washing all that negative energy down the drain. Its so relaxing and really helps a lot!
Do try a few different ways and see which ones you're most comfortable with.