The Hammers avoided relegation with two games left to spare last term following a difficult campaign.
However, O'Brien now wants the team to build on their survival and secure a higher finish in the table when they return to action.
"We kept a lot of clean sheets and that was the base for the season. When the times were tough the defence and clean sheets kept us going," he told the club's official website.
"Towards the end of the season we were able to build on that and get enough points on the board.
"We want to kick on next season. I'll be working hard in the summer to try and get back into the team for the first game of the season."
Injury problems saw O'Brien limited to 20 appearances in all competitions for West Ham during the 2013-14 campaign.