1. Inform everyone duties of each division and individual, and principles of time management. This can quickly make everyone be self organized and motivated.
2. The business logic. All company knows how to inform engineers this part. Usually it's done by ask the new engineers to use the product.
3. Coding style. Soon after an engineer is hired he'll begin to code. Then making sure everyone work in the same coding style can help greatly on creat code that fit well to the company's existing system.
3. Code refactoring, Object oriented design, and the use of basic frameworks. Because engineers are from different companies, with different backgroud, this train is crucial for creating reusable and consistent code.