Telling your friends and family is nice, but it won't generate serious traffic. There are more than 100 million blogs out there. Your best bet is if your blog shows up well in Google searches on your topics. But getting your blog to be well-regarded by Google requires that they must first become aware of you. Check out Google Webmaster Central. You can learn a lot there. Whatever makes Google happy will probably work for other search engines too.
Probably the most important factor (to Google)is getting highly-ranked sites to link to yours. For that to happen you need to post good material, and then tastefully mention it at other blogs that may be interested. No one wants self-promoting spam to be posted on his blog, so you should only mention your blog when it's appropriate. Don't resort to obnoxious practices like mindlessly spamming other blogs with links to yours.
In time, you'll have other sites linking to you, and Google will notice this during their routine crawling of the internet. You'll get better placement on Google searches, and that will bring you traffic. This is the tried and true method. Slow and steady. It works. Beware shortcuts.