Hello it's my first post here :). You don't know how to write a proposal right? Ok here's my suggestion. Proposal is formal kind of letter. First of all you have to plan (for example:Proposal about your county) your proposal.
A. Think of all the aspects of your country that are significat.
B. Chose the ones you could tell about.
C. Decide on three main heading, and select the best items form your ideas.
1. Introduction: Must be short and attractive to attract someones attention.
2. About three headings: ^^ its your ideas you think of. Remember to show only positive things, its really important in proposal.
3. Conclusion: Should be really interesting. Conclustion should also show that your (country or whatever you want) is the best in the (world.....).
I would be happy if this could help you:)