I usually think of first past the post as a system where you're voting to keep someone out, not voting to get someone in.

I think tactical voting is the only way, and we should be promoting that as much as possible.

Forward Democracy us the best source of tactical voting advice in my opinion. I think that as "the tactical vote" becomes increasingly known and targeting by parties, we will see a lot of misinformation in this area to try and confuse people to vote for the wrong tactical choice.