Inflate with air or helium, two balloons and tie together. Repeat until you have three sets of 2 balloons. Place the necks of two of the sets together and twist one balloon from one set around a balloon from the other set. You should now have a cluster of four balloons. Place cluster on a table and slide the last set between the balloons of the cluster. You will have to gently move some balloons out of the way to form a cluster of six balloons.
Tie one end of the fishing line to the cluster. If the cluster is filled with helium, tape onto countertops, tables or tie onto chairs. If they are filled with air, hang from the ceiling, rafters and anything else that is overhead. Either way, the balloons will look like they are suspended in mid air.
5 inch balloons are also available at most party supply stores to make smaller versions of bouquets, columns and clusters.