When you have great ideas that you would like to share with others to encourage people to do something according to what you are thinking, then it would be best to create a very good proposal letter.
The proposal letter, if it is intended for a person of higher authority, should be done the usual format that we do formal business letters. However, in this proposal letter format, you will have to make it explicit yet concise. It should be explicit in a way that you get straight to the point with your proposal but it has to be as brief as possible. It is to consider the limited time that the person you are writing to has in reading the letter. There should also be the idea of urgency and necessity so the other person will be urged to positively agree with your proposal since that is what you want to happen. Respect and prudence should also be observed as you write to make it more appealing and emotionally convincing.