First, focus on your core competencies. If you don't have a degree in English or journalism, you can still improve your skills by taking continuing education writing and editing classes, and it never hurts to take a seminar occasionally to help you brush up on your editing skills. However, it's your primary job to make the site's content compelling and relevant to your audience. It's one of the best places to gather information about the field and to learn how others are using online media to communicate, entertain and inform. There is a huge and growing market for online editors and writers who know how to communicate via the Web and who understand the principles of writing for this medium.
Salaries vary a great deal depending on experience.
Don't forget to use common sense. Write well, edit like crazy. Include attention-grabbing, meaningful headlines, links and subheads. Avoid using jargon and buzzwords. Be direct, clear and concise.