I cut some Peter Pan Silhouettes out of vinyl with my Cameo, along with the happy thoughts saying, then popped them onto a glass jar. If you don't have a cameo, you could always print out the design you want, tape the paper to the inside of the jar, then trace the stencils on with paint on the outside of the jar. Easy peasy too, just a little more time consuming waiting for it to dry.
Fill it up with all your happy thoughts throughout the year. It doesn't have to be handwritten notes either. Pop in some ticket stubs, charms and trinkets. Whatever reminds you of your happy times!
For less than $5, she has a custom happy thoughts jar that she loves!
How do you keep track of your happy moments throughout the year?