To track my newest little ones growth I made month stickers. I simple used clip art added text and ran them through a sticker machine.
These are some that show off the stickers the best. There is a few things I would do different if I did it again.
1. I wouldn't try to match the month with the sticker I would add things to the background
2. I would also focus more on the number, like the 1st month.
3. I would use different colored onesie and maybe an outfit