These are all vocational careers that have a high competition for places. These careers require hard work and self motivation. If you constantly need your sixth form tutors to run after you demanding work from you, then think again about studying these subjects. There will be hours of studying to do.
Make sure you find out the qualities needed to be a good doctor, vet or dentist. Do these qualities match up your personal profile. Making lots of money is not the prime motive for entering these careers!!!!!!!
Besides excellent grades at GCSE and AS level, you need to prove that, not only are you intellectually suitable, but can communicate and articulate. These careers are not for the retiring shy person who mumbles and who cannot express an idea.
You need to show that you have a high level of interest in people/animals; you cannot ignore the world around you and your community.
You must have relevant work – experience and at interview you will be expected to talk about your experiences.
Many universities use self–centered and problem based learning in their courses involving group and individual work. You need to develop suitable study skills to help you cope with the high expectations.