I tell current 3rd years:
< 225 Step 1 = ~90
> 225 < 230 Step 1 = ~80
> 230 Step 1 = ~60
> 230 < 240 Step 1 = ~50
< 240 Step 1 = ~40
Obviously more goes into application review, interview invitation, etc. but this is a good rule to follow for the simple reason that most schools have screening figures that don't allow the passage of especially < 225 applications. It's their one metric and so they use it. If you did well on Step 1, but have low publications and marginal reputation letters, maybe you should consider more than what would normally be suggested. You're an adult, use some logic there.
I highly agree with the 2 or less residents opinion. If your coresident is a pain, you'll have a ****ty 3 years. The work is going to be shared.
I'm on the fence about location stuff. I was really impressed with some places I probably never would have picked on location alone. I'm not suggesting that the above person is saying consider that alone, but I'm saying stretch yourself a bit here. For example, I interviewed in Madison, WI and I thought it was an awesome residency with the nicest people; but I hate cold weather. I ranked it high because of how surprised I was. If you go by location alone, you might run into a school in a cool place but with poopy reputation/curriculum.
I also highly agree with the push notifications. Sometimes there will be competitive date selection (like first-comers get a Friday and not a Saturday), which may preclude you from making the interview if you have an interview two days before (for example).