If you're interested in learning how to make birthday cards for friends you could just duplicate this example.
Grab a couple of coordinating paper patterns and cut them in different sizes. I took a couple patterns from the Abigail Rose Designer Paper packet and attached them to the front of the card. I wanted to use the striped pattern as an accent to the floral one, although I think I'd like it better if I had made it just a bit narrower
A scrap of Petal Pink Cardstock was used to stamp the greeting in Early Espresso Ink. I selected that color because it's one of the colors used in this paper collection and coordinates with the striped paper. I cut it out with a flag die from Stylish Shapes.
NOTE: You can pick up all of the items to recreate this birthday card for your friends below.