I have always preferred to tape a knot or bow behind a layer of cardstock instead of trying to wrap ribbon around a piece of cardstock. It's hard to get the length right and the ribbon likes to slide off if you don't use an adhesive. Knots are easy and you can tie them "in the air," but bows are more tricky. I have found that tying them around something round, is just the trick for bows. I start by finding something round that is the right size for my project. Glass jars and drinking glasses work very well. In this first picture, I used a Stazon cleaner bottle, though I don't recommend using bottles with liquid in them.
Next, I slide the piece off the bottle, so I have a bow with a loop:
I then cut the loop with a straight cut (as opposed to the angle cuts of the bow ends) - which I will use to wrap around the card piece.
Now the straight ends are wrapped around the cardstock and taped in the back. This allows you to get a nice, tight bow and ribbon. This layer is then added to the card base:
This is a GREAT way to create a "wrap around" bow on your project.