A few comments :-
1) Why is ProjectID in the Customers table ?
2) Your CustomerProjects table implies many Customers can be involved in a Project - is this true ?
3) In the EmployeeProjects you might need to allow for Employees to be on a Project for different periods of time.
4) For style, I recommend putting the foreign keys directly after the Primary Key.
5) On my Database Answers Web Site, I have over 60 Customer-related Models that you might find interesting.