For starters, I'd say it would be best to take advice from people whose careers and accomplishments are to some extent a matter of public record. Then you can evaluate (a) whether they seem to have actually accomplished the things they're trying to teach you to accomplish, and (b) whether they seem to have accomplished those things via the procedure they're encouraging you to follow. If yes to both, then you might proceed further.
In that case, the problem of making good advice seem too easy might come down to a couple of things. First, you want to see a good step-by-step procedure where you can really understand each step and imagine exactly what you'd have to do to achieve it. Second, it would be a red flag if any of those steps seem to be "magic" steps such as "Have a brilliant, lucrative idea for a business."
Advice about what to do if you have a brilliant idea for a business is still valuable for some people.
Lukeprog has done some great posts talking about how scholarship has benefited him personally and how to do it. However, he hasn't talked much about how to tell the good from the bad, and I think this is an especially big problem with it comes to "how to"s, rather than standard academic subjects.
The thing is this: writing on academic subjects tends to be dominated by academics seeking to gain status from their work. Not all fields have a strong correlation between status and making actual discoveries, but many (perhaps most) do. So for academic subjects, the big challenge when it comes to making sure you're not reading nonsense is to try to evaluate the soundness of the field in question.
When it comes to seeking out "how to" advice, though, writing on the subjects seems to be dominated by people looking to make money selling advice. That means that if bad advice will sell better than good advice, they'll give the bad advice. Even if their writing includes legitimate advice, they have incentives to give a distorted picture of the subject they're writing on if it will sell better (for example, making whatever they're talking about sound easier than it really is). In some cases, advice books end up trying to nudge you towards buying some more expensive thing the author is selling.
So: when you're researching a "how to" topic, how do you tell the good advice from the bad advice?