Swati Dwibhashyam in Quota for question on how to build one's capability for higher studies.
Application for going abroad is different in the sense that our overall dedication to our field is guaged. So here are a few things I think you should concentrate on-
Academic performance- Make sure you have a stellar academic record. Since you are still studying, you can work on this and increase your score every year, so that your aggregate percentage of 4 years is really good.
Research work- Undergraduate research is a beneficial add-on in your application. If possible, you can publish atleast two papers by the time you finish your degree. Research work shows your interest in your subject beyond the required curriculum. Also, you can present papers at conferences. Even the number of conferences you participate in, counts.
Co-curricular activities- Activities like organising dental camps, health check up camps, giving seminars, participating in symposia, etc will strengthen your CV.
Extra-curricular activities- Universities are also interested to see what you can bring along. So extra-curricular activities like volunteer work, being a part of NGOs or clubs, etc can give you the extra brownie points.
Work experience- Apart from the one year of rotatory internship, while studying itself see if you can start to either observe or assist a practicing dentist. This way you understand the professional setting better and you'll have work experience in hand.