Accounting Software

What is the best way to sell software hosting service for business applications to companies?

If I have a data center where I can set up the servers and the necessary software, what is the best way to sell the hosting service where I will manage and support the business applications for companies? Basically, I will be the outsourcing company for the applications and off-loading the work from the client companies. I plan to host business applications such as accounting software, HR/Payroll, CRM, ERP, etc.
As a professional applications hosting company, I will be able to host customer’s applications more efficiently thereby reducing the cost.