Lie your fabric out on the cardboard and iron out all the wrinkles. Remove any loose bits of string or fuzz.
Using a small scrap piece, or the corner of your fabric, test your color prior to printing. For example, the first color I chose ended up having a weird consistency and it would have been difficult to change colors halfway through. Prep steps are a necessary evil.
Pour a small amount of your ink onto your inking plate and roll your brayer in the ink until you have a light, even layer. Roll your inked brayer over your block (or potato) and wipe up any globs or drips. Then, start printing! Use even pressure and apply your block to the fabric. While you may be tempted to double print (print twice without inking the block) don't do it. You'll get an uneven and sloppy-looking piece of fabric.
Keep printing. Yes, it takes a long time, but put on your favorite tunes and enjoy yourself! Print in straight rows (unless you're doing a sporadic design) and don't sweat the little mess-ups... it's part of what makes your fabric unique.
Et voila! When you're done printing the entire piece of fabric, wash all your tools in warm water (use soap if necessary) and allow your fabric to dry for at least an hour. Have a cup of tea. When your fabric is dry to the touch, flip it over and iron the back side with medium/high heat to set the design (be mindful of what your fabric can handle.)
Now you can use your sweet new fabric to add your own flair to anything... like reupholstering a chair or making a throw pillow!