First of all, you need to have the time in service and time in grade requirements met before being promoted to the next highest rank. Some services require you to sit for promotion boards and other services require a written test and an oral interview. There may be a requirement for you to have so much time invested in upgrade training in your specific career field also along with having career development courses (CDC’s) and PMI (Professional Military Education) requirements met.
@Hydrogenbond Not really. But expect your supervisor to notice what you’ve done in your mission. You’re not the only person who seeks for promotion in military. A good/close relation with your supervisor will allow you to get certain(or special) mission that only a few trusted subordinate will have this opportunity. Complete that several times,and your supervisor will consider to give you a promotion. Because you deserves that. But it would be hard to build close relation with your superior. Since there’s a limit that differentiate subordinate status with superior status.
Excellent performance, passing exams, time in grade, and special duties like II and drill instructor taking courses offered to advance in your field, and in some cases like paratroopers they may advance quicker because slots open up for them more as their comrades have to drop out due to injury.
In the Navy, it takes a combination of good evals, good test scores on the advancement exam, and the needs of the Navy. Some ratings are impossible to advance in since they are top-heavy and don’t need anybody on the next paygrade while others are so open that if you have enough TIR (Time In Rate) and sign your name on the advancement exam then you get another stripe/chevron.
Personally, I was E-3 just for going to Boot Camp and got E-4 after completion of A-school because I went Nuclear. Nukes (and a couple of other schools) can get E-5 for just turning their 6-year hitch into an 8-year hitch, but “STAR-babies” are almost universally despised.