I found more these on Pinterest too for ideas for the party decorations.
The pom poms I took 10 sheets of tissue and did an accordion fold and then in the center wrapped a wire around the center and then hot glued some ribbon on the edge of the outside fold. Once the folding is done gently pull the tissue apart. I found this tutorial on YouTube helpful.
Here is how mine turned out.
When it came to the sign I ran out of time to draw the characters, so I asked Ethan to draw them and then Noah and he colored them. I made the actual sign as they worked on the characters. Kera wanted the sign to be placed on a dowel rod and placed next to the mailbox. Ta da... presenting our sign.