Basically, the designers used the same technique as I did (foam brush), but they applied a thin coat of primer first (I tried primer, but found it it didn't make too much of a difference with the product I was using). The InStyle team applied the labels in a different spot and more free form. I really like the look.
Chalkboard Paint: Pea Pod and Periwinkle (Rust-Oleum chalkboard tint base)
Jars: Ikea Burken Jar
Have a great day,