Make it easy
The key to cultivating long-term, profitable business relationships is making it easy for your customers to work with you.
Source: Sales trainer Adrian Miller
Be flexible in what you offer and in how you conduct business. Avoid the "one size fits all" approach and tailor each business relationship to the client's needs.
Flexibility is a must if you have competition. When you are rigid with what you offer, you are giving your competition an edge.