All you can do is research your issues and your candidates and vote accordingly. If you're really motivated, get out there and encourage other people to do their own research. For my Marines, I print out both sides of issues, as well as the views of all the candidates that are running. I then hand this out to them, so that they can do be informed. I'm not allowed to sway them one way or the other, regardless of my own opinions, but at least they have the facts in front of them!
Get out there and do something!