1. Background your candidates -- We've already talked about this, but it's important. Who are these folks? Who are their friends and supporters? Who is endorsing them? Who is giving them money? What's their history? Where do their private and public histories intersect?
2. Illuminate candidates' stands on the issues -- You'll get some of this by covering debates, forums, press confernces, speeches, etc. It's important not only to cover what they say, but to verify the accuracy of it. Track their comments on an issue over time to see if they changing the tune. Are they pandering to the crowd? What issues are they ignoring? Are voters' opinions on issues being solicited? In call of this, be sure to put the issues in context. How does this affect my readers?
3. Cover the "horse race" -- The press overdoes this, partly because it's easy, but it still matters. Pay attention to the polls (Are they credible? Valid statiscially?). What strategies and tactics are the candidates using? How effective is a candidate at organizing, raising money, etc. How is the electorate changing? How are registration and voting laws affecting the process? Look for oddities in the collection and counting of votes? Is the process fair?