Rovers impressed against the promotion favourites at Loftus Road, being only the second team to take points of Harry Redknapp's side at home this campaign.
Now as they prepare to face the Lions at Ewood, the midfielder believes Rovers have to kick on.
"It is the inconsistency that is frustrating, one week we can be really good and we look like we are a team that is going to get automatic promotion, and the next game we can be a team that is struggling," said Williamson.
"I think that if we can hold ourselves together and just be consistent, which is going to be the key, then I think we can be up there.
"I think as a minimum we want to be in the play-offs and I think we can achieve it if we come to places like QPR and get points.
"We've raised the bar and now we can't let our standards drop, this is the standard we've got to achieve week-in, week-out.
"It is very important, home and away we've got to put a run together to get us up the league.
"It is going to be a good time for us, we've got three games at home so we want to take maximum points and hopefully see where that leads us."
Tickets for Saturday's match at Ewood Park against Millwall are currently on open sale with prices from £15 Adults, £10 Seniors and £5 Juniors.
Book online today at www.onerovers.co.uk
and collect your tickets from the Blackburn End collection point on the day of the game.