Some things never change, respecting the employee and honoring their value with the company, allowing them to grow and contribute, creating a Team natured company, when one goes up all go up, and understanding the family units of employees are as important as the employee themselves. Access to the backend and the infrastructure of a company is also key to retaining employees, people want to be able to know who and what it takes to make an enterprise successful. And making sure that people feel valued, when the company is profitable, everyone should be recipients of the resources they have helped to bring in.
Investing in the education of employees and acknowledging their work in a positive way also creates a work environment people want to remain in as long as possible.