Seriously: The two mistakes I see with people and blogs is (a) spending too much time reading instead of doing, and (b) reading blogs which don't align with their own business, and therefore the advice therein isn't necessarily good FOR THEM (even if awesome for others!), and therefore is perhaps even worse than a waste of time.
Now you can tell I'm being honest because (a) implies you shouldn't read my blog after all!
Here's how you can attack (b). Decide on some fundamental characteristics of your business such as: Bootstrapping or Funding? Wanting to run forever or wanting to sell someday? Wanting to grow large and be the CEO of a 1000-person company or wanting to stay small or even stay single-person? Business model (SaaS, installed, hardware, marketplace, freemium, etc).
Now find bloggers who tend to give advice to the particular type of business you have. This can be difficult sometimes, but at least you have a lens or filter. Some of it is easy, e.g. 37signals and Joel Spolsky is about bootstrapping and staying small but profitable, whereas Ben Horowitz and Paul Graham are about getting huge with funding on online high-margin tech businesses.
And my blog? Well, you'll just have to read a few hundred articles to figure that out. :-)