The Baggies are second from bottom in the Premier League, but have improved in recent weeks.
"The defensive side is getting better and better, we need to keep that nice and tight," Allardyce told reporters.
"If we get eight or nine clean sheets from the next 13 games, we'll have a chance.
"What we have to do is keep applying ourselves as well as we have done and be consistent in our performances and get a little bit better each game.
"Certainly we have to get more clinical in front of goal.
"The sad thing is since I've been here we've only won one when we should have won at least four and the last two.
"Next week becomes an even bigger task to try to go out and win because it's a need to win now basis."