The 22-year-old failed to pick up a single medal from the five disciplines she entered at the London 2012 Olympics, one event less than on her debut at Beijing 2008.
Individually Halsall finished just shy of the podium in the 50m and 100m freestyles, ending fifth and sixth respectively, and failed to make it into the final of the 100m butterfly.
And as part of Britain's 4x100m freestyle and 4x100m medley relay teams, things didn't get any better for Halsall as they finished fifth and eighth respectively.
On the whole Britain's swimmers failed to deliver at London 2012 with the three medals won below the target of five to seven and UK Sport cutting their funding as a result.
Halsall's failure to medal hit her hard, she kept a shoulder injury a secret so keen was she not to use it as an excuse and locked herself away from the post-Games celebrations.
But she proved she hadn't lost it at the World Short Course Championships in Istanbul in December where she took silver in the 50m freestyle as Britain won six medals in total.
And, with Halsall believing she was overworked in the build up to London 2012, she insists having more of a say in what she does can have huge benefits come this summer's World Championships.
"The main thing I did wrong was that I did too much," said Halsall, who won world 100m freestyle silver in 2009 and is now coached by James Gibson after Ben Titley's departure to Canada.
"I did too many metres in the pool in the build up. I also learned I should take charge of what I do, be more in control.
"We had good results in Istanbul, it shows we still have good swimmers in Britain. We still have fire in our belly as a team, we showed that in Istanbul despite all that's said about us.
"I took responsibility for myself and enjoyed that. It is what I will do more of in future. I'm getting my confidence back and looking forward.
"We all want to improve in 2013. It's the World Championships in Barcelona in the summer and all my training is geared towards that."
© Sportsbeat 2013