In order to be on top of the project, project manager has to know inside out of the whole deliverable.
Scope, budget, time-line. All these will lead to project quality.
Project Manager cannot lose directions in the entire delivery. Or else, Project Manager will led and managed by the team member instead of the other way round.
Project Manager cannot lose track on the scope.
He has to ensure the team member delivers what has been engaged and approved, no gold-plating. Whatever promised in the requirement or scope, PM has to deliver. Do not deviate from the original project goals.
Project Manager has to ensure the spending has to use within approved budget. Do not over-spend cos Project Manager will have to justify why the project is spending additional funds that was last proposed and approved.
Do not lose track in the project spending. Have a worksheet to track and monitor all the items that needs to be spent and how much was actually spent.