how appealing residencies are depends on the person. i'd refrain from calling some things more appealing than others. for instance, i'd rather be attacked by a bear than be a cardiac surgeon 😉.
it's a tough question to answer in a post. as a 4th year med student you'll apply to the residency specialty of your choice through the NRMP.. you need letters of rec, a personal statement, etc just like any other application process. you get interviews and rank the places you interview from first to last. they rank you in comparison with other people they interviewed and a computer tells everyone where they're going for residency sometime in mid-march. residencies vary from 3 to 5+ years to complete and often there are optional fellowships to further specialize when you finish. for instance, a surgeon could do a fellowship to be a vascular surgeon, an internal medicine doc could do a fellowship in GI or renal or cardiac etc. some residencies like derm, neuro, radiology, ophtho and a few others require a 1 year internship in something more general before starting them. competetiveness depends both on the type of residency you're applying to and the specific program, and is too specific to these variables to explain succinctly. cheers.
