Liverpool's No.33 made more first-team appearances than ever before - 32 - scored some memorable goals in Europe and made his England debut.
"I think this has been one of the most important [seasons] in my career so far," Shelvey told Liverpoolfc.com.
"The last three months has been a bit stop-start for me. The first part of the season I was enjoying my football but the last three months I haven't been because I haven't had as much game time as I would have liked.
"I suppose looking back I have played a few games in the first team, had some crazy moments and good moments. I would say it has been a good season for me personally.
"I made my England debut as well and I have learnt a new way of playing football with the new manager coming in. The defensive side of your game helps your attacking side so I feel I have learned that.
"It's nice to have a manager like Brendan who plays the young lads and has trust in you to go out and prove yourself."
Shelvey netted four goals for the Reds during their Europa League run, including a memorable header at Anfield against Udinese - and it is his European form which has given the midfielder most satisfaction.
Explaining his best moment of 2012-13, Shelvey added: "Probably the two goals I scored against Young Boys.
"Coming off the bench to get the two goals was good but then the following Saturday I was sent off against Manchester United so it was a bit of a rollercoaster week.
"I would have liked to have scored more goals, to be honest. I had some good chances to get more but there's only Hendo and Stevie who have got more goals from midfield than me, so that's good."
Regarding his hopes for next season and the areas of his game he feels he can improve on, Shelvey insists he is eager to get the chance to become a regular in the first XI at Anfield.
He added: "I think sometimes I've got to be calm and cool it down on the pitch because I'm quite aggressive, but then again if I take that out of my game then I wouldn't be the same player.
"You can have people telling you 'You can't do that and can't do this', but they are not on the pitch so they don't know what it feels like to be on the pitch.
"I just need to get a run in the team and play 10 games on the spin when I don't come out of the team."
On Liverpool's hopes in 2013-14, Shelvey believes there is no reason why the Reds can't make a concerted fight for a top-four finish and return to the Champions League.
He said: "I think progress has been made. We had a few draws last season and if we could have turned them into wins we would have been looking at a third- or fourth-place finish, but I think next season that will happen.
"This has been a rebuilding season with a new manager coming in and getting his style across, and I think the players are picking up more and more each day.
"I think the manager will hopefully bring us a couple more players in that will get us some more goals and obviously we need to replace Carra.
"You can't replace the man but if he brings in a few more players and gets us more attacking style then I think we can finish in the top four."