Whether it's a vertical, horizontal, thick or thin banner it's up to you but here is an easy way that you can achieve the look. Cut a strip of cardstock or designer paper the length you'd like (for my banner: 4 3/4" x 1 3/4") then at one end of your strip you need to measure and find the center of where your notch will be (for my banner 7/8"). Add a pencil mark to the center and then you need to measure from that point up at least a half inch or more and add another light pencil mark. Once you've done your measuring all you need to do is cut from the outer corners of your strip of cardstock in to your second pencil mark and voila you've created a banner.
For my card I used the cute new stamp set Holly Jolly along with the coordinating Holly Jolly Die.
Here are some examples of using banners on your card by a few of our Trendsetters: