Here's a short checklist of things you can do to increase your readership, traffic, and visibility. These things are critical if you expect to make any money with your blog.
Write Often -- Search engines don't check your website daily, but they will return to your website more frequently if every time they return there is new content to peruse. Human readers are the same.
Focus long-term -- Generally speaking, older pages have a higher page rank than newer pages. If you consistently add new information about the same topic, the first pages on your site will gradually increasing in page rank.
Stay Focused -- Websites that stay on the same topic will receive the greater portion of the searches on that topic. Don't change the theme of your website. If you're getting to the point where you can't write anymore on the same topic, start a new website, don't change the subject of your old one.
Keep in touch with readers -- Read comments on your blog, respond to e-mails, do everything you can do to enable two-way communication. Down the road you may get too busy to respond to your readers individually, but in the beginning if you don't respond to them you'll never get to the point where you have too many readers to keep up with.
Be Informative -- People will come to your website for two reasons, to be informed and to be entertained. If you want to entertain it's better to create a presence on a website designed for entertainment such as a video server like YouTube, or a social networking website such as MySpace. Most stand-alone websites should be focused on information. You can be entertaining during information delivery, but the main motivation for people to seek you is information.
No Excuses -- This is one of my pet peeves from my days in radio broadcasting. One of the general rules is never apologize on the radio. The people who heard you make a mistake, if it bothered them, have already changed the channel. The people who are listening to you now just tuned in, and weren't aware of your mistake. The most common excuse I hear from bloggers is apologies for not updating frequently enough. They take two months off and presume that their readers have been hanging around idly, and impatiently, waiting for them to update. In reality their readers they had two months ago have moved on, and their new readers don't care that the last post is two months old. Focus on the readers you have today, not the ones you may have lost. If you have to take a break, just take it, knowing that your readership will go down.
Take out the Trash -- Dead links, spam comments, ads for last month's holiday should all be removed as soon as you notice them. Don't just blog, become a reader of your own blog. As you read click the links, visit your advertisers, and read the comments. Delete anything that is confusing, or will annoy your readers.
Shorter Homepages Are Better, Most of the Time -- I'm a big advocate of tons of content. I've said it a hundred times, and will say it hundreds more... "Content Is King". However, if you're running a blog, try to limit your home page to just a few posts. The more posts your home page contains the longer it will take to load. If you have two or three posts on the home page or readers will get used to "clicking" for more content. Remember readers to click are readers who generate solid advertising revenue.
Dumb down Your Website -- I'm not talking about content, I'm talking about presentation and functionality. Eye candy graphics are fun, but when they don't work or are slow to load they frustrate or your readers. Video game websites are particularly bad when it comes to this. They think they have to have the coolest graphics, when actually most gamers prefer highly functional websites. If your website is database driven, it's much more likely to fail. Use high-technology on the back end only when functionality warrants it. Don't use complicated code just to make a website visually interesting.
Use Relevant Images -- Using a few relevant images to your posts adds tremendous value, but don't overdo it. Generally speaking, I like to have one or two images for a blog post and three or four images on a webpage. Make sure you use Alt tags so the search engine (and screen readers for the visually impaired) know the content of your images. Whenever possible let your text flow around the images. Your readers will have a better experience with fewer reading interruptions.
Give Them the Good Stuff -- Good content is important. If your content doesn't add value to your life, it won't give much to your readers either. Try to impress yourself. If you can do that, your readers will be far less critical. Improve your content, your depth of information, and your own writing skills.