Some Churches will squander your money lobbying government to further their own agenda, while paying no tax. Instead of donating money to a church (which spends a percentage of your money on worthy causes, and the rest proselytizing), give directly to secular and humanitarian groups having low managerial overhead, and no secondary agenda. Notable groups include:

No matter how you choose to spend your money, avoid giving it to churches or anyone else with an expensive administrative process. Encourage your parents to read about other noble causes and support those instead. Where possible, donate directly to the people who need help. Sometimes you need look no further than your own neighborhood.