2014 is the last year you can take the “old” MCAT before it changes. The “new” MCAT, which will debut in January 2015, will be longer and will have a social sciences section. I took the MCAT in 2013, so I'm going to discuss the “old” one.
The pre-2015 MCAT consists of three sections: Physical Sciences (general chemistry and physics), Verbal Reasoning, and Biological Sciences (biology and organic chemistry). The science sections last 70 minutes each, and the verbal section lasts 60 minutes. You get a break between each section. All the questions are multiple choice, and you get no penalty for guessing. The test is scored out of 45, and the mean score is around a 25. Different medical schools have different median scores (for example, the median score for accepted applicants at UCSF is 35). Most people aim to get in the low 30s. You can take the test as many times as you like, but medical schools tend to look down on those who take it more than twice.
Different people have different strategies for tackling the MCAT. Some people don't need a prep course, while others like the prep courses. Some take two weeks to study; others take five months. It's really up to what feels best for you, and what your budget and time constraints are.
Here's how I studied for the MCAT: first, I set aside two and a half months. I took the test over the summer, when I didn't have many other commitments. I also took a Princeton Review Prep class, which met four times a week. Not only did the class help me brush up on my sciences, but it also gave me a schedule to follow. This level of structure was particularly helpful for me. For the first two months, I focused on content. I reviewed the lectures, made flashcards, and did practice problems. I would routinely quiz myself on topics I struggled with to make sure I really had them down. Sometimes I would pretend I was explaining the concepts to someone else. To practice verbal, I just did passage after passage. Eventually I would time myself on the passages to make sure I wasn't spending too long on them. I also got good at answering the verbal questions without reading the passage. This is an important skill to master; many people find they cannot read all seven verbal passages in just 60 minutes. If you know how the MCAT likes to ask the verbal questions, it's somewhat easy to pick the correct answer to question without actually reading the passage. On my real MCAT, I only ready six of the seven verbal passages and still did fine. Finally, about two or three weeks before my actual test day, I started taking full-length practice tests every other day. Taking those are the best way to prepare for the actual exam. During those last few weeks, your scores will start to rise exponentially as you get more and more used to the format of the exam.
It's important to remember that you should only take the real test when you feel 100% ready. I postponed my test day a week because I felt I needed an extra week to really get it all down. This was probably the best decision I could have made; my scores went up by several points in that last week. Only take the real MCAT when you get practice scores in your target range. And most importantly, don't give up. The MCAT is an extremely difficult test to master. It's easy to get frustrated while you're studying. Just remember to keep your goal (medical school) in mind.