I found my inspiration on a Russian blog/ site (didn't understand anything) but never mind, I just needed the picture.
I decided to make a two piece outfit because it's easier to change diapers like that. I bought 3 pieces of fabric: jersey, shiny fabric and jacquard fabric. The vest is just a mock vest, attached at the front and it finishes in the side and shoulder seams.
But I must admit that it's cute to see a small baby with a bow-tie.
How to make a bow-tie: http://www.makeit-loveit.com/2014/04/little-boy-bowtie-the-quick-and-easy-version.html
The shirt is my creation: will make a link
found on a Russian site: https://vk.com/shop_zigzag