if you see an option with a write in part, write in someone instead of casting a vote for a candidate you don't like.
if there's not an option to write in your choice, don't fill that part out.
someone else commented and talked about being in a place where everything is pretty much dominated by the republican political machine. in those cases it might be better to focus on mutual aid and working in local county and town meetings instead of attaching yourself to a party.
if you've got the time, putting the screws to someone in a county board of commissioners meeting over spending a bunch of money on the local cops riot gear that they never use instead of straightening up peoples screwy culverts is a sure win.