I matched in a fellowship this year. Here was my timeline, for what it's worth, for the ACGME sports, going through the match. Pain and non-accredited positions are often earlier. Ask around in the specialty you're in. For employment, the list below is still worthwhile.
PGY-2 year: nothing, save up some money for application fees, flights, and moving costs. It's a good idea to get these documents together (in PDF format) for fellowship/employment applications:
- USMLE step 1, step 2, and step 3 score sheets and/or COMLEX scores
- Medical degree
- Undergrad, grad school (if applicable), and med school transcripts
- ACLS and/or PALS certifications
- Medical license
- Professional photo
- Certification of intern year
- Any publications, including abstracts
- Any other accolades (AOA, awards, etc.)
- Immunization records (including flu shots, TB, etc.)
- n-95 mask fittings
- Birth certificate (yes, seriously)
- Driver's license scanned
- Social Security Card scanned
- Marriage certificate if you changed your name
PGY-3 year: continue to save up some money. End of the year, start thinking about a personal statement. I asked for letters (PD, plus 2-3 others) around May or so, I think. Keep track of your procedures! At some point around the end of your year, you have to register for ERAS and NRMP - I don't remember the exact dates unfortunately. Don't forget to apply for NRMP as well.
PGY-4 year: Get the letters of rec in, finalize personal statement, enter in your application. Wait for interviews. Interview (October/November). Rank (December). Match (January). Coast.