Despite struggling for regular starts last season, Defoe ended the campaign with 17 goals in all competitions.
He is now hopeful of keeping his good pre-season form going, and is keen to take his chances whenever they come.
"Not playing regularly is frustrating but all you can do as a player is make sure you are still around and still in the squad," he told The Sun.
"I've always said that once you get a chance, you've got to take it and after that you leave it down to the manager.
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"What I would say is that every time I get called up for England, if I'm fit I'll be ready and will always give it my all."
However, the striker says he will not let the disappointment of not playing affect him, and will always try to make an impression on the training ground.
He added: "If you speak to the manager, he will always tell you I work hard in training. I am not one of those players that will sulk or anything like that.
"I just keep it going because if you sulk and then do get a chance, your head has gone and you can't really perform.
"I've never been a sulker. I've always waited for my chance and when I get one, make sure I grab it with both hands. Even though it is early in the season, I enjoyed getting the goal.
"You want to have a good season for the club and always feel you have got something to prove."