For those applying to medical school this cycle, if you haven't already, it's time to start asking for letters of recommendation (LOR).
Beyond simply fulfilling requirements, you want to get the strongest letters you possibly can from the most influential writers. Choosing the right individuals can be a challenge, and advisees often ask me what to look for in a letter writer. Here is my suggested wish list for potential letter-writers:
1. Explicitly state they will write you a strong LOR
2. Senior faculty
3. Weighty academic titles
4. Well known in their field
5. Spent significant time with you
6. Experienced letter-writers
Of course, all of these qualifications are not possible for all writers. But the more of these you can garner the better.
With regard to #1, don’t be afraid to ask a potential letter-writer if she will write you "a very strong" LOR. It may seem awkward at the time you ask, but, believe me, getting a wimpy letter will be much thornier. If the faculty member says no, hesitates, or tells you in March that she has to plan her Thanksgiving get-together ;), politely thank her and move on. Although disappointing, acknowledge that she has done you a huge favor. You are far better off avoiding her letter, and you now have the advantage of substituting a stronger LOR written by someone who loves you.
With regard to #2 through 4, admissions officers are human just like the rest of us: Receiving a LOR from an accomplished, known colleague will be weighed much more heavily than one from someone deemed less successful and unfamiliar. If you are better connected to someone without a title, consider asking the professor (a more senior person who has a weightier title) if she would consider writing the LOR with significant input from your closer contact (i.e., the TA who taught your section, or the postdoctoral fellow who directly supervised your research project). That way you get a LOR that includes insight from someone who knows you, signed by a name that packs a punch.