Lets cut down on these threads lets just post a few general rules so that we don't keep covering the same ground all the time. I will get us started and others feel free to add their 2 cents. If it is informative enough, we can sticky it and it can be used as reference for new 4th ys in the future.
From my experience and talking with successful applicants at several places from previous years and this year:
All new applicants should look at the Match Data report released each August as that is the most up to date raw data on matching. Some of the data from this year will likely change slightly (for example, Step 1 scores have started to drift up some over the last couple years).
Steps 1 and 2: through this last year of applicants, to "know" you are in good shape, mid-230-240s and you are the average successful applicant....low 230s is borderline and depends on the rest of your application. If you are 250 and above then Step 1 is not a problem for you and it is better to not take Step 2 and risk dropping (although this is unlikley as most do better but safer not to). If you must take Step 2 due to your schools requirments, then don't release the score until you have seen it (and if lower don't release at all until match is over). 220s and below, you should really think about taking Step 2 early and getting in the 240s.
AOA: Helps but not a magic bullet nor is it an application killer with out it at even the competitive places. If you have strong clincial grades, good step 1 and good letters you can match at good places without this. If you have all those things and AOA then it can help move you up.
Clerkship grades: Surgery and Medicine are the two big ones followed by Peds and OB and everything else after that. If you can pull a couple of Honors with one being in Surgery or Medicine then you are in good shape. Some programs look for a certain number of Honors in clinical clerkships as a cutoff for interviews so the more the better. HP is better than P so several HPs can help. No honors is a red flag at some programs but does not mean you cannot match radiology. It will hurt you at the more academic programs.
Research: Any is good, more is better, it does not have to been in radiology but you better understand what you have done because it will come up on interview days. To have a shot at Harvard programs, Duke, Wash U it is a must. Most other places, not as big of deal but still helpful and something they like to see. Some respected university programs do not put a high value on it and actually look for residents with just a passing interest. A PhD and to a lesser extent MS is a great addition to the application and will generate interest from academic programs.
Location: As a rule, if not a coast or big city program, the closer you are the better it is. Some programs will only interview applicants within a 2-3 state radius. Really competitive programs (eg MGH, BW, BI, Duke, Wash U, Cali programs, U Penn and Hopkins) will interview the all stars from all over without much concern over location.
Aways: Can help you decide if the program is right for you and will show your interest. Almost every person I know that has done an away was offered an interview. It can hurt if you leave the wrong impression but seems to help more people than it hurts. About 1/2 the people I know that have done aways have ended up residents at one of those programs. This is especially helpful if you are a great person to be around and on the cusp of competitiveness for that program or from an area/school that does not normally match to that program.
Program rankings: There are a bunch of lists around. There is one used on this site that in absolute terms was not very reliable but in relative terms was not bad. The reality is that some programs have a great reputation that may or may not be justified but may not be best for the applicant. The bottom line is that the individual needs to choose a place that provides the best learning environment for them, be that more/less research, more/less call, more/less pressure, big city/small city, academic-research program/pure clinical program etc. Know yourself and what kind of environment you need to be your best and what your ultimate goals are (for example, does the program have a Fellowship in your likely field), and rank according to those criteria for you.
Others from current or past classes please add your own perspective.
