Parkinson feels the Bantams were too easy to defend against during the majority of last weekend's home fixture with Port Vale and he wants his side to be more threatening as an attacking force when Crewe arrive in BD8.
Parkinson said: "I felt Port Vale's goal last weekend set us back a bit and we were poor in the first half until (Mark) Yeatesy's free-kick goal just before half time.
"Second half was better for us, we were a lot more positive in our play, but we still need a performance this Saturday with more energy in it. We need to be more of a threat to the opposing team.
"That means more crosses coming into their box, more shots on their goal. I just felt last Saturday we didn't hurt Port Vale enough, certainly in the first half.
"Whatever the system or whatever the personnel, the games we have done well in are the ones where we have had energy in our team, more attacking runs off the ball stretching the opposition, more dangerous balls in behind their defence.
"We were a bit easy to play against last weekend, certainly in the first period."
Opponents Crewe are currently rock-bottom of League 1 with only one win to their name all season.
Steve Davis' men have also conceded 27 goals so far this campaign - the highest in the Football League. Twelve of those goals have come in their last three league games, leading to defeats against Milton Keynes Dons, Colchester United and Notts County.
Despite going to the Alexandra Stadium to watch Crewe's game with Notts County on Tuesday, Parkinson says he won't be speaking too much about this Saturday's visitors to his players.
With the possibility of Crewe making changes in personnel and in their formation given their poor current run of form, Parkinson feels it is best to focus more on his side and what they can do to try and win the game.
Parkinson added: "I am not going to speak too much about Crewe to the players before the game. That is no disrespect to them at all, it is just we know they might change their starting eleven or their formation.
"They have just got beaten on Tuesday so they could easily make changes and it might be hard to predict their exact line up. We have seen them in a number of their recent games so we know they could also play a number of formations come Saturday.
"I just want to see us perform better in terms of us showing more energy, more drive and more determination as a team.
"We owe that to our supporters. They have been very patient with us over recent weeks following a few home losses. It is very frustrating for us because a lot of our better displays (this season) have been on our travels.
"They goes for individual players and as a group. Now is the time to show that at home.
"The only way we will do that is by working as hard as we can against Crewe come Saturday."