When writing a request for proposal it is essential to remember that you are creating a formal document for publication. As such, the document becomes a reflection of not just you but of the organization as well. Therefore, the proposal needs to be clear, organized and detailed. Before you begin to write your proposal you first need to narrow down what you want. Then you need to take that list of what you want and narrow it down to what you really need. Lastly, you need to take the list of what you really need and compare it to what is really feasible.
While you are doing this, get feel for what kind of response you are seeking. Each vendor will respond differently and with their own aspect of where the focus should be placed. For example, some will focus on the quality of the work, some will focus on lowering the cost or some will focus on the desired timeline (Reh, 2013). Where do you want the focus of the project to be placed? Three important sections of a request for proposal would be the statement of work, the assumptions and constraints and the terms and conditions. The statement of work (SOW) defines the project objective and scope of work. Provide the vendor with the company’s background and services so they can gain a perspective on the business and its needs. There needs to be detailed list of contract data requirements and system specifications (Jones, 2011). Remember that this is the part that will be the driving force of your selection, so the more details you provide on the project, the better the responses.
You should specify your expectations by listing the criteria that you will be looking for in vendor responses. For example, they must include the software product drawings, engineering tolerances, service levels, projected timeline to include detailed deliverables and milestones, technical requirements, business conditions, hardware and software functionalities and/or requirements and risk assessments (Bucki, 2013). If you don’t provide a detailed statement of work, then you will never get the desired end result.
The assumptions and constraints should be anything that you feel the vendors will need to know. Such as the type of environment they will be required to work in i.e. is it a secured area or will they need to be escorted? Do certain teams that require input to the project work different hours? What hours are the vendors expected to work? You should also address overtime, travel expenses, upgrade or modification costs and licensing rights. It is best to be straightforward in this section because failure to do so could result in serious complications during the course of the project. These complications could cause a halt in the project due to the renegotiation of the contract. If anything, it will cause an unnecessary strain on the working relationship of all parties involved (Bucki, 2013).
Lastly, there are the terms and conditions. Now some people might think that this could be worked into the assumptions and constraints, and to be fair in some cases it probably could. However, I look at this as the deal breaker. The types of items you can included here would be funding options, duration of contract, options for renewal, warrantees, penalties for failure to meet project deliverables and the levels of service. If you list these in their own section and in order of their importance, then the vendor will be able to provide a more honest and fair assessment in response to your proposal request (Bucki, 2013).

References
Reh, F. J. (2013). How to write an RFP. Retrieved 4 December 2013 from http://management.about.com/od/money/ht/WriteRFP.htm
Bucki, J. (2013). Request for proposal (RFP) and request for quotation (RFQ). Retrieved 4 December 2013 from http://operationstech.about.com/od/vendorselection/a/VendorSelect-RFP-RFQ.htm
Jones, J. (2011). Defense AT&L. Software acquisition: reducing risks. Retrieved 4 December 2013 from http://www.dau.mil/pubscats/ATL%20Docs/nov_dec11/Jones.pdf