NCEA and Scholarship exams begin today, starting three-and-a-half weeks of swotting for more than 146,000 school students.
The Qualifications Authority has printed 620,600 personalised examination booklets for the 119 exams.
In addition, about 5140 students at 55 schools will sit some of their exams on computers as part of a trial.
Year 11 students from Newlands College in Wellington said they were nervous about sitting their first NCEA exams.
Isaac Andrews, 16, said he was "mortified" even before the exams began, and Isha Bhatnagar, 16, said she found exams "nerve-wracking".
The students agreed that smartphones were a particularly bad distraction from studying.
"All it takes is one little ping on the phone," Isaac Andrews said.
Madi Ulusele, 16, said turning her phone off didn't always help.
"If you have your phone off you're wondering 'is someone messaging me right now?'," she said.
Senuka Sudusinghe, 15, agreed.
"When you turn it off you think, 'oh yeah I've turned it off'. Then you're like, 'wait, did this person text me, have I got an email from this?'"
Deb King, a deputy principal at Newlands College, said the school encouraged students to use digital devices for their learning, but teenagers did need to ignore them when they were studying.
"Study is a really important part of learning that you have to put your device aside to an extent," she said.
"Do your learning, gather as much information as you can out of that device, but put it aside when you actually need to get that information into your brain because it's very much harder if you're constantly getting pinged by notifications."
In addition to phones, the students warned that friends and late nights could also hinder their study.
"Don't stay up all night because that's what I do sometimes - it doesn't work out," Isha said.
Senuka said studying alone worked best for him.
"Studying with friends it is a bit of a disaster. Nothing really happens when you're with your friends and you get distracted easily," he said.
Isaac recommended using pen and paper, rather than computers for revision.
"You can only do so much on a computer I find. On pen and paper you can underline, highlight, illustrate and emphasise the things you need to study more," he said.
Qualifications Authority deputy chief executive, Kristine Kilkelly, said students needed to be well-prepared for their exams.
"They should be focused on making sure they know their subject matter, when and where their examinations are, and what they need to do to achieve their goals," she said.
The NCEA and Scholarship exams finish on Friday, 1 December.
NZQA tips for effective study
*A place to study: Students need a quiet, organised and well-lit space to study. Set regular routines and study goals. Students should talk to their family or whānau if they need more quiet time, or a different place to prepare.
*Revision: Students need to know what is required to achieve each standard and should have up-to-date notes from their classes. They should practice using resource pages on the NZQA website that include previous years' examination papers and past examples of student work.
*Be prepared: Students should make sure they know where and when their examinations are, and get there at least 20 minutes early. The examination timetable is on the NZQA website.
*Balance study with free time: Students should take regular breaks, eat well, get fresh air, stay in touch with friends and study groups, and get plenty of sleep - especially the night before an examination.