A successful logo is one that is SMART:

Simple: Your logo should be classic and noticeable. Less truly is more.

Memorable: When someone needs a product or service that you offer, you want to be the first brand that comes to mind. Stick in your customer's mind with a memorable logo.

Aesthetically Pleasing: After all, your logo is a piece of art, so why shouldn't it be stunning? A beautiful logo stands out among the rest.

Relevant: Your logo should be appropriate for your industry. For example, your popsicle stand logo should not communicate the same emotions as a trash company.

Timeless: Don't think trendy, think long-term. You don't want to rebrand or have an outdated logo in 5 years. A proper logo should stand the test of time.