I'd suggest you find a banner that looks good and use it as a model. I'm not advocating plagiarism, but since you apparently don't have access to educational facilities, a good way to learn is by copying...
I have a friend who is a student photographer and has entered a contest to fund their dream.
My friends' dream is to go to impoverished areas in South Asia and South Africa and photograph the unfortunate lives of these people. These areas are the most poverty ridden areas of the world! If they win the contest, they win $50,000 to make this dream come true.
But here is what makes them deserve to win, instead of using that money for themselves and to produce everything, they are taking that money to fight hunger in that area and spread love! They are using as little of that money as possible for travel and tech stuff and they are donating the rest for these people.