Gossip Girl actress Cassidy will play the comic character in The CW's new drama.
"It's a little intimidating, yeah, but when you're so in it, you have to let that stuff go," she told Collider. "You can't think about it 'cause then it just gets in your way.
"I try mainly to just focus on character and what my character's point of view is, with each person, and try to figure out story. I'm just there to do my job."
Cassidy added that she is "really excited" about resuming filming on Arrow in July.
"I think it's going to be really, really fun," she predicted. "I'm working with a great group of people, and everyone is amazing and really talented. I'm really lucky to have been given the opportunity to do that."
The 25-year-old star - who has also appeared on Melrose Place and Supernatural - suggested that fans of the original Green Arrow comics will enjoy the new show.
"Hopefully, we do it justice and everyone is happy," she said.
Stephen Amell - who plays the title character in Arrow - recently hinted that the show could feature Black Canary, the superhero alias of Cassidy's character.
Arrow will debut on The CW this fall, paired with Supernatural on Wednesday nights.
> Arrow voted most exciting new CW show by Digital Spy readers
Watch the latest trailer for Arrow below: