If you don't feel that you have the necessary EMC know-how when you start a project, it can be a good idea to get some help from experts. This will keep you from making mistakes that may cost you a fortune to correct later on. There are a lot of consultants, agencies, and companies specializing in EMC design and EMC training. Adding more people in the design phase will also reduce design time and time to market.
Good EMC design requires a lot of knowledge, but you do not have to acquire this knowledge the hard way; by trial and error. Others have done this already.