Cruise ship insider reveals simple booking trick for scoring a better cabin

She also works as a guest presenter on high-end cruise liners for several months out of every year.

Finlon said her experiences at sea have taught her how passengers can improve their onboard experience - starting with when and how they book.

Her top tip? Book your next cruise while you're already aboard your current one.

"If you book onboard with a future cruise consultant, [he or she] can give you great [information] and better cabins," Finlon said.

She also recommends speaking with a cruise consultant face to face - plus researching cruise lines before booking.

Amenities, layouts and onboard experiences can vary widely, she noted.

Many travelers book cruises without fully understanding the cruise line or what's included, she also said.

Finlon's perspective is shaped by a career connected to cruise ships and time spent largely aboard them. 

"When my husband [or I] work, there are no days off - it's an everyday job while onboard," Finlon said.

Finlon has worked on cruise ships since 2011, she said, after deciding that a traditional nine-to-five job was not for her.

"There's always something to do - and you meet new people from all over the world."