Check out how the pros do it
Bertil Horberg, the creator of the fantastic Gunman Clive series, was once asked if he would create a level in Super Mario Maker worthy of his premier franchise. He declined, saying he already knows how painfully difficult level design is. Other developers, however, have stepped up to the challenge.
If you're tired of wading through those god-awful tough-as-shit levels, or the automated levels created solely for the purpose of sharing on YouTube, then check out the GameDevsMakeMario Tumbler page. It's filled with levels designed by professionals from across the industry, like Ryan Benno from Insomniac Games and Towerfall's Matt Thorson, who just so happened to create one of those tough-as-shit levels I was just complaining about.
For an even larger list of levels not limited to professionals, there is also MarioMade.com. Here you'll find user creations broken down into categories like Zelda levels and sports levels, as well as more designed by the people who create the games we love.
I can't wait to try some of these levels out once I finish up with all of the ones you guys have created for the Dtoid Designs contest. Speaking of which, if you would like to show off your level-building skills, the inaugural Super Mario Maker Dtoid Designs challenge is still going on. Entries are due by October 15!