If we all stopped thinking that voting for a candidate we actually want to vote for was a waste then it wouldn't be!
It is up to you to make a change in this country and break away from the two party system.
The Conservatives and Labour win every time someone says, "voting third party is throwing your vote away." They have all of the power and we're allowing that to happen. If we don't want to live in a country that's run by two, uncontested parties, then voting third party seems like a good way to go.
Voting for someone that you do not believe in is when it is really wasted. If you vote for a third party - and enough people do - there is a chance that, although they don't win, a spark can be set and that third party can be on the track to becoming a major party.
Choose the MP you want - the system doesn't change because we don't change it.