Capital-raising will be an ongoing process, even if it's only dealing with the investors that have been brought in. Plan on it. If possible, generate increasing sales and profits before seeking outside investors. It will make the negotiation process much easier. Assemble a competent and complete management team.
Management is the single attribute of the company that is most important to investors.
If that is not possible, be prepared to acknowledge its weaknesses and develop a plan or schedule for resolving them. Many successful entrepreneurial firms develop strategic alliances with major players in the industry for the purpose of marketing its products. The name recognition and experience of the larger partner will help in getting the product to market when the company is so young that it's name is not likely to be well known and its industry contacts are few. Investors are often impressed by strategic alliances. Try to avoid a concentration of sales with a single customer if possible.