So according to my experience at the entrance exam and the interview students should not try to hide the weak points of their knowledge especially if they are still finishing the secondary school and a certain topic will be thought to them later.
They should not expose their weeknesses of course if that topic is not asked during the exam.
They should try to learn at least the basics of each topic as except the situation given above (someone still finishing the secondary school) the examiners usually test the overall knowledge and not just a deep knowledge of a given topic.
They should be decided about why
1. do they want to study medicine/dentistry/pharmacy etc...
2. do they want to study that at the University of Debrecen
3. do they want to come to BMC instread of 1st year or vice versa
4. did they choose physics or chemistry as I usually asked these from the students and if they are determined that makes a good impression in the examiner.
During the BMC they should visit the lectures and seminars to be easier to study the material of the given subject (Biology, chemistry or physics).
It is even more easier if they study week by week and not just try to catch up and learn everything just before the self control tests.
They should use the seminars to ask their questions if they do not understand something and this is only possible if they visit the lectures and study continuously.
Basically that is it what I can suggest to them.
All the best and see you in February.