Along with never stopping writing to hone the craft, you also have to develop a system of research that leads to trust. You have to provide strong, reliable source material. Whether you are writing fact or fiction, you have to get the details straight.
Books give you an added value over internet sources. Books had to pass through a publishing house and en editor. There at least the material had to stand up against some sort of scrutiny before it reached you.
Finally, you need to be very picky on your sources. If one source provides a detail you can find nowhere else and cannot confirm, you probably should play it conservative and set that piece of information aside or tuck it into a footnote and have it ascribed to that author. Never assume a "scoop" is just that. The reason for all the careful research is that you need your readers to trust you if you want your book to succeed (or your article, or post, etc.). That trust is lost when readers discover that your facts are in error. Remember, writer, you are truly human ... but your readers expect a higher level of diligence from you than from other mortals.
For the first post in the "Writing Success" series, see: http://jsbrookspresents.blogspot.com/2014/06/writing-success-never-stop.html