Many schools have an MCQ paper. If your paper is negatively marked it is important to work out beforehand how good you are at guessing. For some reason certain people do better and other people worse when they guess. To work out if you are a good guesser get a practice MCQ book and do a paper with 3 pens of different colours. With the first pen answer questions you are sure of. With the second answer questions you think you may have answered correctly and with the third, answer the rest of the questions (that you are probably guessing). Once you mark the paper see if you gain or lose marks when you guess them. Most people probably gain marks and these should answer all the questions in the real exam. If you lose marks then leave out guesses in the exam. Instead of doing this by hand you can do it online at Clinical Tutor by turning on "confidence intervals."
Most people practice some MCQs before the exam. The advantages are
that you get used to the format and you remember the answers that you
got wrong. There is very real value in finding the past papers of your
medical school as it not a myth that they repeat the questions. There
is questionable value in basing your whole revision around doing
thousands of MCQs. The nature of the exam is that you will get asked
some very random questions during both the practice and the exam.
However it is very unlikely that these will be the same questions! A
better technique is to learn a subject and then answer a selection of
MCQs to reinforce the knowledge. Studies have
found that even if the questions asked didn't match exactly what was
learnt candidates who consolidated revision with questions did better
than those who didn't.
are some links to some online practice