Hi PowerTeacher! That's up to you. What are your plans for your blog? Do you have any goals? Some of my blogs I write to weekly (either 2 or 3 times a week or at least once a week) and others monthly. It depends on my time, inspiration, and what my focus is. Am I blogging for an audience or purely blogging because I like to write? No hard and fast rules.
Register with technorati.com and if you go to
soho-life.com you'll find a list of blog submission directories. There are also others listed here at this forum. That will get you listed and started.
Make it a habit to visit other people's blogs and leave comments - make sure you include your blog URL too. Comments should be relevant or perhaps add to the blogpost in some way - people will come visit your blog if they like what you have to say in comments elsewhere. And of course, belonging to forums like this one helps a great deal too.