Punctuality in students is a rare phenomenon. suggest tips to improve this quality in majority.

I agree that merits work better for most students, we like being awarded and not scolded, However, it should also be to a certain point as you can overload students with praises

As a University instructor, I always face this problem with new students. In University,4 absences from the student result in termination of his course. So the first time I warn him that if he is late again, I place him as absent on the attendance sheet. And I make clear for the whole class that this is my method in dealing with late students. So when any student repeats that, I keep him outside the class and place him absent.3 absences deduct10% of his final grade, and4 absences are DF, drop failure on his transcript. I only gave one student in my whole12 years of teaching a DF, and through out this whole period, my students learned punctuality. 

Tough way but good behavioral method for future employment, punctuality .

Reward program. There should be an award given to kids who maintain perfect attendance, kids who have improved in the marking period, kids who stayed out of trouble (for troublemakers), kids who achieved their goal (bringing up their grades), kids who tell the truth, etc... These little merits or recognition certificates can be in the form of paper using MS Office, inexpensive gestures tell the student that they are1) being watched2) being recognized and it will boost their performance. I can't tell you how many times this has worked in my lifetime as a tutor. Even more as a parent :) 

Well thank you very much for asking me such question.  I think the teaching is not a profession, it is an art, as transfer of knowledge really is a difficult thing.  The only person who knows is the best in the world.  Also a teacher is the one who actually builds the character of his/her students.  If he/she is strong enough then he/she can produce the very good human being.  

Particularly to your question, one has to be a role model.  The kids (5-15) are mostly punctual as they are dependent on their parents.  Whereas the16 and above are the somewhat independent and they might have this problem.  Nowadays use technology is also an option, but first ONE HAS TO BE THE ROLE MODEL.  I would say get their cell numbers, SMS them the lecture topic, time and venu.  SMS1-2 day before and also on the day1-2 hour before the lecture starts.  I hope this will help you and the students to be somewhat punctual, but the first thing is ROLE MODEL.  If you are not punctual, your students could not be.  

Ask your students to offer prayers 5 times a day in congregation at specified time in masjid. Which will slowly make them punctual. In that they need to answer God only.

Punctuality is needed not only on the part of the student, but the teacher as well. Sometimes you find a student more punctual than a teacher and and sometimes the teacher may be more punctual than the student. So, punctuality depends on the behavioral commitment and not only something to adhere to.

1/ Ask him why is he / she  late – be careful and listen to his / her answer (s), then try to analyze reasons  as to why he / she  is always or sometimes late.

2/ Contact the parents and discuss with them the issue.

3 / Make the student share with you solutions to his / her problems of arriving late.

4/ Make the topic interesting and decide when to start by interesting things and when to start giving or asking for classwork. 

5/ Always give some good reasons or interesting short stories of the importance of being punctual.

5/ Motivate the student to come on time.

I punish my students. In a good way. 

First, set a time, a leeway. If your class starts at8am, tell them they can be late until8: only. If they are still late for8:, they will not be admitted to class. For them to be accepted to the class, they will have to secure a letter of explanation as to why they are late and a letter promising that being late won't happen again except for emergency purposes, and that they have to make their parents sign the letter, so the parents will know that their child is late in class. If the student does not comply, he/she cannot enter your class, not until he/she has secured the letters.

Second, once you have entered the room and if there are students already inside and if there are a few more minutes before the class starts, play a song. Say, if your class is at8am and you're in your room at7:am and that there are already students in the room, play a song. Tell the students in the room that if the song ends that's the time that those who are about to enter the room are late.

Third, punish them by making them perform in class. On strips of paper, write different punishments. For example, on a strip of paper you will write "With only a as your vowel, you will sing Mary Had A Little Lamb" or "Dance 'Gangnam Style' like an old man with arthritis." What students are going to do to these is that whoever is late will be picking from these punishments on strips of paper. It is not really a punishment, it is a way of loosening in the class too.

Lastly, pair them up. Make your students have a "buddy." The purpose of having a buddy is for them to be responsible not only for themselves but also for others. Say for instance Student A is paired with Student B and it so happens that Student B is late, Student B will be punished including his "buddy." In this way, they will learn to be responsible for others. Students, by the way, will get to choose how to be punished.

Remind them, too, that if for them their time is important, it is most likely that for others time is important too.

If you mean punctual in attending the class i think you need to creat methods to attract the students and motivate them to be punctual in attending your class. Make the first few moments of the lesson the most enjoyable ones and students will be carefull not to miss your class or be late for it.