Cole, who returned as a substitute in the 0-0 draw with Stoke yesterday for the first time since injuring his hamstring on the opening day of the season, conceded that Liverpool lacked a killer instinct.
Brendan Rodgers' side remain in 14th place in the table, without a win at home this season, and having scored nine goals in seven games, five of which came against strugglers Norwich.
The Reds hit the woodwork three times against Stoke, but it was the outside of the upright each time rather than a close call, and they were chances squandered rather than a case of bad luck.
"There was a bit of frustration in the dressing room after the Stoke game," Cole told www.liverpoolfc.com.
"We felt we should have won the game with the chances we had.
"The only criticism of us that I would have was that we didn't stick the ball in the back of the net. We just lacked that final bit. We have two weeks now to work on it and we're looking forward."
The midfielder insisted that there were elements from the goalless draw that should hearten the Liverpool players and supporters.
He added: "There's a lot to work on but we have got to take the positives out of it. We didn't get beat and we kept a clean sheet, which was important as we haven't kept one for a long time. Now we just need to kick on.
"I know a lot of the lads are now away on international duty, but we have got two weeks to keep going, keep working on things, getting in and around the box and picking the right pass.
He also praised Liverpool's teenage stars Suso, Raheem Sterling and Andre Wisdom for coming through a gruelling encounter with Stoke's large and physical players.
"It was important for the young boys and I thought they were really good again," he said. "I think you've got to match Stoke .They're strong lads and they like to compete.
"Personally, it was brilliant to get back. You're always nervous with hamstring injuries in terms of the first time you come back in. But I felt good and I have two weeks now to work hard and get back up to a high level of fitness."