This is an interesting topic.
I am sure some of the following overlap with what is said above.
In my experience the most important aspects of strategy with regard to digital preservation are the following, in order of importance:
1 HUMAN RESOURCES (Quality and passionate professionals who will go above and beyond and will even anticipate the changes and adapt early before disaster -- obsolescence, risk -- strikes.)
2 COMMITMENT (Organizational commitment is critical to institution-wide awareness, care and action -- along with staff, user involvement and consultation.)
3 RECORDS SCOPES (A clearly defined intellectual, moral and physical extent of the records will guide the appraisal process AND the selection/deselection of what matters/doesn't matter.)
4 PROTECTION (Clearly defined plans for protecting the records from all risks will enable the digital continuity of the records, which is the outcome the strategy is designed to ensure. Protection involves content, context, media, movements, access, malware, software, rights, etc.)
5 STANDARDS (The proven, well reasoned or documented theories and practices that guide appraisal, selection, description, storage, access, protection and maintenance of the records. This has a great deal of influence over their digital continuity.)
6 OTHER RESOURCES (Apart from the human resources singled out above as the number one strategic choice or advantage, other resources cover proper staff retention and technical infrastructures as well as access to state of the art research or literature to maintain the sustainability of the records' digital continuity.)
7 DOCUMENTATION (Knowledge -- especially knowledge that explains the why/how/when/where/whom/what expectation of the record -- whether human-shared or recorded in metadata or other processes, is the essential ingredient in all aspects of the digital object's life. Should unforeseen circumstances lead to disaster, recovery at best and understanding at worst will rely on documentation to make a case for the sustainability, economics, or wisdom of letting go of those losses.)
Those are my 2 cents to the discussion on important aspects of a digital preservation strategy.