Investment-

This speaks to the importance of getting to know your employees on a personal level to help build trust. If you do not take the time to invest in their passions, you as their leader, will not understand the "why" around "what" they want for their future.  

Take the time to listen to their hopes and dreams and what gets them out of bed in the morning.  

For companies that do not have the means to provide salary increases, finding ways to increase benefits/PTO banks, other perks, goes a long way with employees. 

Lastly, find ways to empower your team to give back to the community and to themselves. This all rolls back to taking the time to invest in them, hear what they want and ensure to follow up and not let their voice go unheard.

Opportunity can be enough, if you know what it looks like to your team.