First, gather all your supplies,
You'll need freezer paper, scissors, your pre-washed without fabric softener fabric (in my case the fabric, bag handle and sewing machine) the color of paint you want to use and a bottle fabric medium (I got it at hobby lobby, it's about $8) as well as an iron and ironing board, foam or other unimportant brush, a pice of unneeded cardstock or cardboard, cup to mix the paints in and an idea for the image you want to use.
(if you are going to make something from the fabric, do that now, so that you know the approx. size of the image you will need)
1. Start by tearing off an appropriate sized piece of FP (freezer paper) and use a pencil or pen to draw your image onto the matte side making sure to leave a blank border area of about 1/2".
2. Then, using either a pair of scissors or if your image is very detailed, you may want to opt for the craft knife, cut out the image leaving the surrounding paper.
3. Now iron your fabric on the appropriate setting so that the area to be stenciled is as flat as you can make it, and then then take your surrounding FP and lay on top of the area. Position it carefully, and then using the iron set on the warmest non-steam setting iron the paper to the fabric with the shiny side of the paper against the right side of the fabric.
4. When moving your fabric from the ironing board, be careful not to bend too much, the bond between FP anf fabric isn't strong, if it separates in the process, repeat step 3.
5. Mix the amount of fabric medium with the indicated amount of paint (usually 2parts paint to 1part medium) and place your cardstock or cardboard behing the layer of fabric that you will be setncilling. (see below image, that is the bleed-through from my stencil)
6. Using either a dabbing motion of you can spread the paint from the outside in (start on the FP and spread towards the empty part of the stencil) apply your first coat of paint. If you fabric is plain, this may be all you need, if patterened, usually a second thicker coat is necessary. Let this coat dry some (about 30mins), and see if more paint is needed. If you need to apply more and the FP sencil is beginning to separate from the fabric, you will need to use the spreading motion to make sure that you don't get any of the paint outside of the stenciled lines.
8. Once the fabric is dry enough to touch without being tacky, you will need to heat-set the paint. Use a scrap piece of cloth, or if that's not available, a paper towel over the paint, and iron at the fabric's appropriate setting for 20 seconds by placing the iron and lifting straight up, and placing again. If you iron normally, there is a chance the paint will smear, so in the beginning of the heat-setting process be very careful.
9. At this point it is recommended that pieces meant for heavy use air dry for 7 days. Then you can clean the piece with warm soapy water and/or wash on the gentle cycle and air dry.