You need the ability to work with Executives. This means that you understand the industry, the buzzwords, the requirement to assist executives. Typically, you work your way up through the company. You may already have knowledge of the industry through formal education. The industry could be finance,energy,medicine, systems, insurance, risk management, etc. An employer looks for an easy integration into the company. A typical EA does not need much training. You should ask what technologies they utilize. Experience with the appropriate technologies will be a positive aspect of your skills.