1. Get a lot of friends to help you! Get crackin early!
2. Come up with a concept. This works best with a few people of varied skills. Include creative people who can picture a theme come alive, and practical people who can translate the vision into wood and screws.
3. Build a frame around a trailer. We did a 2-layer box: 2x4 on the bottom of the bed, connected to a 2x2 around the top perimeter. This let us attach anything without needing to attach to the trailer itself (which gets the trailer's owner to let us use it again next year). We also hung an extended piece past the wheel base to let us cover the outside all the way to the ground.
4. Build your main design components. In our float here, we made the leprechaun and the dice first, then added the chest of gold to fill out our space and add deeper texture.
5. Make signs to display your group and cause for all the spectators to see. Next year, we'll add chalkboard sides to make an easier, permanent mounted signs.
6. Touch up the finishes. Tablecloths, cardboard, chicken wire, bulk fabric, spray paint... They're all your friend at this stage!
7. Get together ahead of time, dress up, grab some candy to hand out, and have fun!