How you decorate and what theme you use are completely up to you. Since it was close to Christmas I used that for my theme.
I cut the circle first and then used my Planet Punch template to line up the tree punch (Double Framed Christmas Tree) from All Night Media. The greeting was done in Microsoft Word and the center piece for the circle was made in Kaleidoscope Kreator from a picture of Christmas "lamps". A couple small punched trees and two stripes complete the card front.On the inside I added a triangle with a punch out to make a place to write a personal message.
There are many sources for card sketches and here are a few...
Card Sketch a Day
Car Positioning Systems
Inspirational Card Sketches
Card Positioning System
My Sketch World