Agree with the above in that most training programs are relatively high quality. I think the decision of where you should apply is more personally driven since, for the most part, the quality of the training you receive will be the same. Things you might want to consider:
- Geography, particularly with respect to family/friends/etc. If you have a significant other coming along with you, taking into account their preferences might be helpful.
- Your particular interests. Are you interested in psychotherapy? Make sure to choose programs that have strong psychotherapy training. Community work? Think about programs that work in those settings. If you're interested in academia, research, etc., then you'll obviously want to choose a program that has a stronger academic infrastructure in place. And on and on. It can often be difficult to figure these things out prior to an interview or even before you start there, but this is where mentoring and asking around can be helpful.
- Where you want to end up in the long run. Especially if you're interested in academic work, it's generally much easier to remain at your training institution rather than trying to get back to another place as an attending. Not impossible by any means, but particularly for "popular" institutions, you might benefit from doing your training there.
- Ability to moonlight. I'd consider this to be a relatively small factor, but nonetheless it might be something to think about if you know you want to moonlight at some point in the future. Steer clear of programs that don't allow moonlighting if that's something that's important to you.
- Program size. Again, I think a relatively minor issue in the big scheme of things, but there are pros and cons to large vs. small programs.
Of course, how many and which programs you apply to will also be dependent on the "strength" of your application. Again, consider getting a mentor involved to help you make these decisions.
My wife got a lot of input into my program list since she got no say with respect to where I went to medical school and I didn't want to drag her along somewhere that she didn't want to go to. I was also interested in psychotherapy and wanted to make sure I went to a program that had better-than-average psychotherapy training built into the curriculum. After that, my decision was largely based on geography and my gestalt impression of the program after the interview. Did the staff seem attentive and to care about residents? Did the residents generally seem to speak positively of the program? (Surprisingly, this is not always the case) I didn't care all that much about "prestige" of the program, so that sort of thing didn't play a role in my ranking, but that might matter to you and might be worth considering.
This is why it's hard to give general guidelines for this kind of thing - it really depends on what matters to you, what you want to get out of training, and your aspirations in the future.