Make the sign as big as you can without causing an obstruction or safety hazard. When it comes to signs, bigger is better to attract visual attention.
Use matching colors in your design. One strategy is to use complementary colors, such as red and green, yellow and purple, or blue and orange. Another strategy is to use colors that are grouped together in the spectrum, such as red-orange-yellow, yellow-green-blue or blue-purple-red.
Use big, bold text. Make sure the text is clear and easily readable. Outline the text in white to differentiate it from the background if the background is colored.
Decorate the sign with flashy ornamentation. If you want to go all out, decorate your sign with stars, streamers or balloons. If you plan on drawing decorations on your sign, consider using metallic ink or paint to really grab attention.
Create a border around the edge of your sign to tie everything together. There are several options for creating a border. You can use black or white, or you can use a color that matches another element in your sign.
If you're looking for a more durable or long-term solution, contact a sign printing company. Use the design principles outlined in the previous steps to create a digital design with a program such as Photoshop or Gimp. Submit this design to the sign printing company and they will professionally print it on a durable surface such as a vinyl banner.