Every project, I always fumble the start. This also could be due to fact, that I kick off a new project with new customer every 6 months. Having a behavioral preference for being numbers driven , I prefer hard data collection with which the project plan will be near accurate. Making guesstimate is most uncomfortable situation.
So my own checklist will be
1 .Can you delegate more work to customer. DO IT FIRST.
2. Customer Education (I am posting a new one under "Project Literacy" - includes project team literacy as well)
2. Schedule Plan FIRST. Schedule Plan FIRST.
3. Don't take it on your plate, if you have not done it before and the stakes are high (less time, more work for you, etc)
4. Report Report Report!! This is hardly followed as it is kinda more administrative and mostly good things only happen which is taken for granted.
5. Escalation is a bad word. So if things don't go your way start reporting daily, saying the phase is crucial.