How do you define a professional strategy in project management?

Result + Resources + Managing actions

If you want professional strategy & standards for project Management go to PMI .

The Project Management Institute (PMI) tried to standardize project management procedures and approaches in Project Management Body of Knowledge (PMBOK) which presents a set of standard terminology and guidelines for project management.

Version1 was released1986 & the Fifth Edition2013.

But of course you will have to put your own touch based on the project circumstances & risks