Instructions
Expand the size of your nightclub. This can be an expensive upgrade, but it is one you will have to make eventually. Expanding the size of your nightclub includes the fee to furnish the extra space and is the most effective way to make your club less crowded.
Remove any unnecessary items in the nightclub. Poles and statues can be great for decorative purposes, but they take up room that can be used be make your club less crowded.
Kick people out, especially those that are not paying high price. You should use this as a last resort, as your club will lose a small amount of popularity; but, if a patron is not spending money, you can always kick him out to make more room for the customers who are spending money.