Before you start selling,
This is not as hard as it sounds if you have the help from others with the right expertise. In fact it can be done in a week or two in most case if you have already done you market research.
Therefore you need some time and energy from all 5 key skills sets of business development and launch. This can be an expert in each area with management experience or a CEO level person with high level experience in managing all these disciplines. Each piece must go through several iterations and be backed up with solid market research that includes conversations with prospective customers and much more. Ideally these should all be completed before you start a real burn rate (ongoing fixed costs) so that you can take your time without as many money pressures.
Bob Norton is the author of four books on growing companies and CEO of C-Level Enterprises, Inc. which helps companies grow more rapidly with products, training and consulting.