It is also an excellent way to evangelize.
There is one tip that seems to be a no-brainer to me. If you want to reach potential converts (and not merely those who already love Mother Church), you need to give special thought to the labels you attach to your posting. For that matter, your title is hugely important as well.
For example, my recent postings have included the following labels: D.L. Moody, Emmaus Retreat, United Methodist, preacher's daughter. These labels are not likely to gain Catholic readers. They are likely to pull in evangelical Protestants who are googling words/people which are familiar to them.
If your number one goal (as a Catholic blogger) is to evangelize for Mother Church, whenever possible, you should link up your posting to labels and titles that serve as a calling card for non-Catholics.
What is your unique history? I'm a former evangelical Protestant preacher's daughter. There is an entire register of words that I can use to pull in evangelical Protestant googlers.
What are your specific hobbies? What roles do you play? Where do you live? These hobbies, roles and geographic locations could be used to pull in non-Catholic readers who share these things in common with you.
Sure, blogging is fun. And you are likely to have lots and lots of Catholic readers if you have an overtly Catholic blog. But if your goal is to evangelize a little bit in the process, make sure your titles and labels don't merely "preach to the choir" - be sure they reach out and grab the googler that isn't Catholic yet. Your blog posting may reach them in their teachable moment. Your posting might actually become a moment of grace.
Never underestimate the power of a google when grace is working in tandem with it.
