Agree with above. At a mid-tier residency as well and matched into the top fellowship in my subspecialty. Key is sparkling letters (endorsing good operative skill, ability to work with others, normal person), tons of research where you are the primary researcher and phone calls by your mentors during interview season. Remember that even if you are not a fancy residency program, you may have faculty members that are leaders in their field and have connections to the top fellowships. People at bigger name residencies may have an easier "in" to the top fellowships due to the power of their mentor's phone calls, but if you work hard and are productive academically, you will have a shot. Phone calls/communication by mentors to fellowship programs does play a pretty big role though, so just be aware of that. If your program does not have well connected faculty in your desired subspecialty, try to go to meetings/courses where you can meet academic leaders in the field and that can help too. Good luck.