1. Use an appropriate greeting
2. Introduce your topic in a single sentence
3. Add details to your topic in a short paragraph (this could be done in a couple of paragraphs but make sure you don't have too much paragraphs 3 max.)
4. Add a call-to-action to explain what you need the other person to do.
5. Use an appropriate sign-off with your name.
Do you have all these things in your formal letter?