Generally, medical schools require two science and one non-science letters of rec, and sometimes an additional letter from a coach or boss. How do you get a strong letter of recommendation? Start by getting to know some professors. At UCSD, there are hundreds of students in most science classes so making contact is not easy. Try going to your professors office hours in the first week of class. Better yet, go to as many office hours as you can early on in the quarter. From there, it's hit and miss as to which ones will be worth attending. Some classes will have 20-30 students in office hours. And in this is the case and you are attending mainly for a letter of rec, you'd be wasting your time to stay in on these sessions. Try to find a professor with five or less students attending so you can ask some questions and introduce yourself. Lower division science classes are often great opportunities for this because, let's be honest, most people are procrastinators and won't bother pursuing professors for letters until they are doing all upper division coursework. So if you are still taking lower division classes, beat the rush and go to office hours. I can't tell you how much this helped me in getting mine. Once you've found a potential professor(s), try to attend their office hours as consistently as possible throughout the quarter. You may have to ask fairly knit-picky questions, but it's worth going in so your professor can see you are trying to understand the material and that you are a consistant studier. It's also good to talk about other extracurriculars you are involved with so they can include this into his/her letter of recommendation. Meanwhile, you should obviously be working for a high grade in this class or else the teacher won't be able to say much in regards to your work ethic or mastery of the subject.
After one quarter, you can ask for a letter. Although, it's better if you can take another course with him, work in his lab or be a TA.
If you are a UCSD student, once a year, you can get a dine-with-a-prof card and eat for free in the faculty club. Aside from eating some bomb food for free, this is another great opportunity to get to know your professor. This will give him more things to say than just "Sally was a nice person and got an A in my class on quarter."
If you are not a UCSD student or you have already played the dine-with-a-prof card for that year, you can ask him or her anyway to lunch or coffee. This takes COURAGE, but hey, so does being a doctor and these out of the classroom meetings are important for establishing a personal connection.
Once you've developed a relationship with your professor, go ahead and ask the dreaded question "would you be able to write me a strong letter of recommendation to Medical School?" Ask it this way instead of "could you write me a letter or recommendation to med school?" If your prof will not write you a strong letter, and you are not desperate for one, you should look elsewhere for someone who will positively write about you. A professor rejection might actually do you a favor by allowing you to avoid a mediocre (or poor) letter of rec.
Hopefully, a rejection or apathetic response doesn't happen, and instead your professor says "YES! I would love to!" In this case, give your prof a due date and a packet with the career services information letter. You should waive your right to see the letter because this makes it more convincing to medical schools.
Ask your teacher if he would be comfortable with you providing suggestions as to what she should write. Professors will usually say yes because they are doing a favor for you and would like to include what you want them to say. Then, pick two or three positive characteristics that you believe you posses and have shown to the professor. Provide reasons for each. For instance, if you think you were not only a focused student, but a positive contributor to other student's learning, mention that she should write about this. Then support it. "In certain office hours, I asked others what their questions were and then helped clear up their confusions." Print out a paper with these suggestions, and generally, the professor will incorporate them into his letter. This way, you will better ensure a positive and supported letter. Professors generally love this too since it pleases you and gives them less work.
In summary, look for personal opportunities to connect with professors, consistently meet up with them, display your strengths, ask for a STRONG letter, give them suggestions and you are done!
