To me, the worst advise is what I see in magazines for "skill level". I've never taken a class...only done reading and researching and a LOT of trial and error. Some projects I've done were set for skill level of intermediate to advanced, but the project wasn't that hard. Here's one example that I made after only quilting for a few months.
The only time something is done 'wrong' is if you do it and you don't like what you created.