The Cobblers could break into the League Two play-off spots with a win against the Spireites after three successive league victories.
However, Boothroyd is maintaining a level approach and insists his side can still improve between now and the end of the season.
"I'm pretty level-headed and I'm always thinking about what we can do better," he told the club's official website.
"I think everybody is putting in a real shift at the moment but we have got to be very careful that we don't get too excited about what we're doing because we are nowhere near as good as we can be.
"Clearly we are a lot better than we were but we haven't done anything at all yet. We might be creating a reputation for ourselves which is good but nothing gets won in January.
"We have got to keep working on trying to improve and the next game has always got to be our main focus. We've got to treat every game with absolute respect and make sure that we perform because if we don't then it's more than likely that we will get beat.
"Chesterfield is another marker for us, we know that they've got good players in their team but so have we and its very important for us to get that result."