The Englishman has missed eight games in the last two seasons due to disciplinary issues, including a dismissal after a stamp on Tottenham Hotspur midfielder Dele Alli just 49 minutes into the current campaign.
Shelvey, who has admitted that his development has taken longer than first expected, has also vowed to control his emotions on the pitch in the future.
"The penny's sort of dropped now with me," the 25-year-old told Newcastle's matchday programme. "I know what's right and wrong, on and off the pitch, and I know what you can and can't do. I'm just trying to stick by that every day.
"I know what's right and wrong, on and off the pitch, and I know what you can and can't do. I'm just trying to stick by that every day. It's probably taken a lot longer than what it should do to sink in, but I feel like I'm at that stage now.
"I've just always tried to rely on my ability. But you realise that the way football is going, you have to add other elements to your game to get to where you need to be."
Newcastle, who are just a point above the relegation zone, play Manchester United on Sunday.