My friend Morris, a professional blogger, asked me for advice the other day. Here's a partial answer, with a few apologies to Swift: (and when you're done with this list, do well to read my post about shark attacks).
1. Use lists.
2. Be topical... write posts that need to be read right now.
3. Learn enough to become the guru in your field.
4. Break news.
5. Be timeless... write posts that will be readable in a year.
6. Be among the first with a great blog on your topic, then encourage others to blog on the same topic.
7. Share your expertise generously so people recognize it and depend on you.
8. Announce news.
9. Write short, pithy posts.
10. Encourage your readers to aid you in the technorati top blog list.
11. Don't write about your cat, your boyfriend or your kids.
12. Write long, definitive posts.
13. Write about your kids.
14. Be snaky. Write nearly libelous things about fellow bloggers, notifying them to respond (with links back to you) on their blog.
15. Be sycophantic. Share link-love and expect some back.
16. Include polls, meters and other eye candy.
17. Tag your posts. Use del.ico.us.
18. Coin a term or two.
19. Conduct email interviews with the well-known.
20. Respond to your email.
21. Use photos. Salacious ones are best.