Play it like you've ALREADY locked up the nomination. Don't mention the other Democratic contenders. If asked by reporters about the other Democrats, respond "I'm running against George Bush."
Don't skip important Senate sessions for campaign events in Primary States. Gep was hurt bad by reports of his skipping so many House votes.
Announce, immediately your intention to filibuster Patriot Act renewal.
Your role in the late '80s in exposing Ollie North's Contra/Cocaine operation leaves you uniquely placed to go after the Bushnik's complicity in Heroin traficking by our Afghan allies. This too should be done from the Senate floor, rather than the hustings. Contrast it with the Bush Pee-Test plan, and the Ashcroft jihad against Tommy Chong and other potpipe merchants. Put in an appearance outside Goose Creek, South Carolina's Stratford High School, scene of the infamous armed "drug raid" which yielded no drugs. (Invite the other D candidates to join you there. I'd guess Kucinich and Sharpton will. The others absence will need no comment.