You should treat everyone with the same professional respect. However, find out early if this person is the decision maker. Don't be afraid to ask who the decision maker is right up front and focus your time on that person.
Working without a priority list.
Make a top 10 list of your best accounts and customers and a top 10 list of your biggest prospects. Look at this list every day to keep yourself focused so you can spend your energy on getting the best return on your investment.
Relying on technology rather than on relationships.
Sales are made from relationships, and it's difficult to establish relationships on a computer screen. CRMs are great but they don’t sell the car for you. Keep e-mails short - remember, they're great for passing information but can never take the place of one-on-one communication.