If you feel particularly passionate about firearm education, save the less controversial aspects for someone else to claim. Speak up about those aspects that mean something to you, such as the importance of firearm education for both children and adults. Every year people of all ages are killed by accidental shootings. The question is, could lives have been saved had there been some form of education around firearms in those households. Ask the question, and take a strong stance on a subject like this. It might raise a few eyebrows, but sometimes that's necessary in order to bring to light a subject that might possibly save lives.
Persuade your audience to get involved in a recycling project. Demonstrate how much of this planet's natural resources are being used each and every year in order to sustain the world's needs. Speak to how much of those resources are being wasted. Recycling is a good topic because not only does it take minimal effort to get involved, but it also creates a maximum impact on the world as a whole. Depending upon how convincing you are, this particular topic could lead to more people getting involved.
Fuel your audience's awareness about the dangers of texting while driving. Demonstrate with a dynamic presentation the fatal consequences that occur when drivers decide to text behind the wheel. Pull together statistics, real-life stories of families who have needlessly lost loved ones because they or another driver was texting while driving. Give the audience a conscience on this issue. Finally, rally support from your audience to help end this needless sort of tragedy. Put the ownership in their hands.