The Irish defender spent the 2013/14 campaign on loan at Championship side Yeovil Town, where he impressed despite being unable to steer the club clear of relegation danger.
The 22-year-old is now preparing to return to Goodison Park for pre-season and is hoping to catch the eye of manager Roberto Martinez.
He has been assured that he will be given every opportunity to prove his worth, but Duffy knows he is facing a make-or-break period in his efforts to become a Premier League player.
He said in the Liverpool Echo: "Roberto told me that pre-season was my chance to shine and he's said to me that if I am where he thinks I am - from what he's seen of me this season - then I'm going to be involved.
"And if I'm not, we'll see at the end of pre-season what we're going to do. It's a big summer for me, it's up to me."
Duffy believes the time he spent at Yeovil has helped to make him a better player, but also admits that stepping down into the second tier has made him all the more determined to succeed at the highest level.
He added: "Having been around the Premier League and the players and that lifestyle, you sort of get into it.
"When you're away from it, you see a different kind of life and it makes you grateful to be where you are at Everton."