Let's be honest: My blog is pretty cool. It's not nearly as popular at Boingboing, Tuckermax, or that weird housewife who writes about her kids, but I have a pretty steady readership who all post comments and get something out of the site. Since I started around a year ago, I've averaged 1200 unique readers a day (half of that is thanks to huge spikes from digg and such). My blog hasn't made me rich, but I've probably made a few thousand dollars, which is a nice side effect. More importantly it's made me a much better writer, and has helped me chronicle the past year of my life.
What I'm saying is this : I can't help you build the next Engadget or WWTDD, but I can help you get started to building a moderately popular blog.
First you need decent hosting and Wordpress. Don't mess with blogger - no one reads blogger blogs because they all look the same and don't have cool plugins that you need. I know you can customize it and all, but stop arguing and do it my way.
Go sign up for www.dreamhost.com and use the code "TYSDEAL" I don't get anything out of it - it just gives you a lot of money off. They include a domain, so pick a good one. You probably won't ever get to change your domain, so pick a good one. Make it memorable and easy to spell.
The nice thing about dreamhost is that they have a one click install for wordpress, so you can be up and running in a few minutes.
The next thing you need is a good theme. Eventually you'll need to make your own unique theme, but forget that for now. The best free wordpress themes are at Fahlstad. They are super professional and easy to read. You should edit the title graphic to customize it so that your site has a distinct look. If you don't know how, just ask a friend who has photoshop to do it. Hey, maybe I'll even do it if I'm feeling nice.
Next you have to figure out what you're going to write about. To make a lot of money, you need to have some sort of niche. I forgot to do that, so I don't make a lot of money. The trade off is that I get to write about my life, which is the only thing I really care about anyway.
It's vitally important that you are really interested in what you're writing about. If you're not, your blog will fail. That's why I'd recommend writing about some part of your life - a hobby, your job, or even your research.
I don't think frequency of writing is particularly important as long as it's regular enough. I read a lot of blogs ranging from multiple posts per day to one post per week. I write about every 3-4 days.
Don't focus on getting traffic at first - focus on writing authentic material. Your writing style should be easy to read with lots of spacing. See how all my paragraphs are pretty short?
Install StatCounter on your site. It takes two seconds and helps you track who is linking to you, how many pages people read, and how long they stay. As you start off it's hard to stay motivated, but seeing that some people spend hours reading things you write helps a ton.
Choose interesting headlines... notice how one of my posts is called "I'm pregnant." instead of "My pregnancy scare"? Which makes you more eager to read the article? Your first paragraph is also crucial - make sure that it entices the reader to continue reading.
Periodically ask your readers what they like and don't like. When I asked, people said that they wanted to hear more about my every day life, which was surprising to me. It changed the way I wrote my blog, and my readership went up.
Don't try to get traffic until you have at least 10-20 posts. Some of my most visited posts are the old ones that people read a year later, so just know that you WILL have an audience, even if you don't while you write the post. No one is going to bookmark a blog with just one post, so don't try it.
Once you have a bunch of posts, start submitting interesting ones (wait... aren't they all interesting?) to Blog Carnivals. It's a little bit of a hassle, but it will definitely get you a few hundred readers easily. If they don't stick around, then take that as constructive criticism - you need to make your site more compelling. Part of that is just having a lot of posts - you never know which ones people will love, so keep cranking away.
Once you write some really good posts, start submitting them to big sites. I've been on the front pages of Digg, Del.icio.us, Reddit, College Humor, and other popular aggregating sites. Most posts won't get onto those sites, but those that do get tens of thousands of visitors for a day, plus several days after where people who saw your site on those big sites repost on their own blogs. Each time you get on one of those huge sites, you will gain more loyal readers that will stick around long after your 15 minutes of fame.
Allow comments on your site, and respond to them when people ask you questions. I sometimes forget to respond, but I try to do it and it makes the site more of an experience.
The most important advice I can give is to start NOW and stick to it. Blogging is a lot of fun, it makes you more observant ("ooh... I can write about this"), and it provides hours of entertainment to the world!
P.S. It's also vitally important that you link to my blog to be successful. Don't question it - just do it.