It really depends on a couple of things. At Learn to Write Proposals we like to look at what the client's needs are and build our proposal around that...however, in order to persuade you need to show how you can resolve the need of client, so you will need to let them know what you are planning to do and the results it will give them.
If you have an existing relationship with the client then you may be able to rely on some of confidentiality. If you haven't (or even if you have) then contact them and ask for a non-disclosure agreement (mutual, not one-way) to be signed.
If it is especially important you don't give secret away ensure that all copyright, trademarks and relevant patents are applied for.
If you need further assistance (such as providing you with a customized mutual NDA or other commercial services) then you can get in touch with me by sending me a private message.
