If politicians and corporations pay attention to one letter, think of what many letters can do.
Get permission to set up a card table in the mall and ask passersby to write letters. Hang a poster telling what you're doing. You can hand out leaflets, talk to people, and get those interested to write a short letter right there. Provide clipboards to write on. You can have several people writing letters at one time.
Plan your target. Who should receive the letters? All the members of the city council? The members sitting on a particular committee? Just one member? Decide.
Prepare a leaflet. Explain the problem. Give the address of the person to write to. Include all the information a person would need to write and mail the letter.
Don't send form letters. A handwritten letter shows that a person really cares. Some groups organizing letter-writing campaigns at malls often use a variety of pens and paper and envelopes. That way all the letters look different.
Get people's names, addresses, and phone numbers. People who write letters care about your problem. They are potential supporters.