United, who start the new League One campaign at Bolton Wanderers this weekend, scored 17 times in only six pre-season outings.
But Wilder told The Star: “There’s still work to do. There are still things that frustrate the life out of me. We’ve got to be more ruthless and decisive in the final third. We are still, a little bit, trying to walk the ball into the net. But we’re playing on the front foot, trying to press and trying to get forward so that’s good.”
United bolstered their attacking options by signing Leon Clarke and Mark Duffy from Bury and Birmingham City respectively earlier this summer while new captain Billy Sharp and Marc McNulty remain at Bramall Lane.
Although fellow centre-forward Che Adams has attracted interested from both Wigan Athletic and Birmingham in recent weeks, sources close to United last night confirmed they are yet to receive any further approaches after rejecting the latter’s £1.7 million offer nearly a week ago.
Both clubs are still thought to be monitoring Adams’ situation before deciding whether to meet his estimated £2m valuation.
Sharp, McNulty and Clarke netted a combined total of 52 goals last season while Matt Done has been restored to an offensive role following Wilder’s appointment. Done was frequently deployed as wing-back by ex-boss Nigel Adkins despite six goals in his first eight appearances for the club.
“It’s not just the lads up top,” Wilder said. “Everybody has got to contribute. We’ve done well goals-wise but I think we can do more.”