Walker says he sets himself high standards to meet.
"I set myself high standards last season and I'm pleased I did, but once you set those standards, if you then fall below them people start to get on your back a little," Walker told Spurs TV.
"But I'm the first to have a word with myself and say I 'could do better'. I've played 100 games in two seasons - that's a lot of games - and it took a while to get in the team.
"I was patient, got my chance last season and I have to keep doing the things that got me a chance in the first place. I want to win things here."