Nigel Clough has acknowledged the Blades must find some consistency in what will be a hectic month of January.
United's 2015 action begins with an FA Cup third round tie against QPR at Loftus Road on Sunday, prior to league games against Preston North End, MK Dons, Rochdale, Swindon Town and a two-legged Capital One Cup semi-final tie against Tottenham Hotspur.
Looking ahead the Blades boss remarked: "Our performances on the whole have been good, but results in the last five or six league matches haven't gone to plan, although we remain in the top six.
"But we are talking about very small margins, very small details in games and at the moment we are getting punished for the mistakes we are making.
"What we are striving for now is the same level of consistency in league matches as we seem to have in cup competitions.
"Against Southampton we defended set-pieces properly, worked hard out of posession and gave very little away in terms of chances.
"But then against Walsall we give away a poor goal minutes after we had taken the lead and against Port Vale we concede two very poor goals, Bob Harris makes a bad decision and gives away a penalty after we had worked so hard to get the equaliser with ten men."
The Gaffer continued: "That is the difference between our level and the top level, in the Premier League players seem to make the right decisions most of the time, that is what we are trying to do here.
"When we do add to the squad, we have to make sure the players are better or different to what we already have, because those small differences could ultimately prove decisive in the second-half of the season."