Tape a number 1 on the canvas then let them finger paint to make their first work of art to hang in their bedroom. OR... Tape their age numbers each year and do a smaller version to send to grandparents and family. Maybe even cards, thank you notes, etc.
Display your babies monthly photos from the first year of their life at their first birthday party. I had a floral and pink themed party for my little girl and I displayed the photos above the drink bar. It made getting drink of lemonade even sweeter!