If you haven’t already decided which way to vote there’s still time, and if you’ve decided you don’t like any of them then at least go and register your protest. This could be by voting for your second choice so that the majority in an otherwise safe seat is kept low, or by spoiling your vote.
Failing that you might want to vote tactically. If you need help with that see the post from a couple of weeks ago.
Here are some of my other relevant posts on election issues:
Please, just go and vote.