The 34-year-old was recalled to the Three Lions fold by Gareth Southgate in March following a three-year hiatus, having impressed with club side Sunderland last season.
After completing a move to Bournemouth at the end of last month to continue his Premier League journey, Defoe now wants to hit the ground running to give Southgate something to think about, but admits that starting regularly for the Cherries is a challenge in itself.
"It's only normal to have one eye on the World Cup," The Express quotes him as saying. "Every English player will want to get into that squad but it's based on merit, so you'll have to play well for your club.
"I'll focus on doing that and then if I get the opportunity to play in the World Cup again, it would be a dream.
"It's good competition [at Bournemouth] and that's what you want as a player. It's no different to at Tottenham because there were always four top forwards who would go away with their national team and England.
"It keeps you on your toes and you know that you have to work hard to get that opportunity and when you get it you have to take it, it's as simple as that."
Defoe scored 15 goals in the English top flight last season, while also netting in one of his two England outings.