The only sure way to provide this input and make sure that the information hits home is a meaningful vote, in which case the government would be forced to take youth interests seriously. It is obvious that other methods of informing policy makers of youth opinion are dysfunctional. High school is a great medium for political awareness. Middle schools keep a fairly common practice of holding mock elections for the president. Sadly enough, traditions like this do not carry on to high school.
Public schools are a great place for political debate.
And if the voting age were lowered, it would create a more politically aware adult. It's well known that 18-29 year olds are demographically significant, but democratically insignificant when election day comes. Young adults are well known for being one of the most motivated and influential age groups in existence, but only when a common goal unites them. It takes a lot to get most teenagers really interested in a political topic. I believe we would have a more informed and educated society if the voting age were lowered.