A vast community of online writers now exists, with many people giving advice to other writers for free, sometimes when asked, sometimes just blurting it out on forum or blog. ;) Some of the advice-givers have even written how-to books about craft or business and put them on Amazon for 2.99, and despite all the good free advice out there, lots of people buy those books.
Whenever you read advice from a writer, before you begin to believe it, do this for yourself: CHECK THE AUTHOR'S BOOK RANKINGS AT AMAZON. If you are published, indie or traditionally, and they have a book or two ranked higher than you, sure, give the advice some consideration and decide if it sounds like a fit for you. If they are ranked lower than you, or if they are ranked (as is shockingly common), lower than 300,000 at Amazon's book store, you can safely ignore that advice. To be blunt, if the advice was good, they'd have more readers.
Subject me to this test, too. Either my proof is in my pudding, or it ain't. (This year, I'm mostly talking about me rather than giving direct advice, but if you see implied advice in my posts, it counts.) My newest book's link is always next to the top "gadget" in the right-hand column of my blog. Usually, though not always, an author's newest book is his top ranked book.
And for heaven's sake, don't buy some book or service from the advice-giver unless he's a top seller! That's being the "sucker born every minute." And none of us wants to be that.