Dizzle, the language is going to be confusing, so I'll try not to use too many acronyms.
It'll take you anywhere from 18mo to 4yrs from being comissioned to getting to your fleet squadron (you get winged in there somewhere). When you get winged, a timer starts, and when you get to your first fleet squadron (JO sea tour) another timer starts. You have timelines for your tours, and you have a timeline for making rank... these are completely independent.
During your tours, you will compete against your peers. Your grading for this competition is recorded in your fitreps. Fitreps go in cycles. Every year during a particular month, everybody in the squadron of a certain rank will get a Fitrep that ranks them against one another. LT Fitreps are in January... so every January, the CO/XO sit down and rank all the LT's in the squadron in order. The top few guys get an EP (Early Promote), the middle few guys get a ranked MP, and the rest of the guys get an unranked MP. The fact that you got an EP doesn't mean you're going to make LCDR "early" in your career... it's just a term to identify the top performers.
For Example:
LT Jones #1EP
LT Smith #2EP
LT Dick #3EP
LT Blow #1MP
LT Suck #2MP
LT Balls MP
LT Jock MP
LT Crap MP
...etc...
There is also a Fitrep cycle for all officers and chiefs every time there is a Change of Command. You will also receive a Fitrep when you depart from a command. You'll probably get 6 Fitreps during a 3 year tour. The idea is that your first 3-4 Fitreps are unranked MP's where you show a good upward trending based on the CO's average (something to learn later) and a strong progression of jobs. Your 4th Fitrep should be a ranked MP, and your last competitive fitrep (called your HI-WATER fitrep) should be a high EP. Competitive fitreps are where you are ranked against all other LT's in the squadrons. If there are 15 LT's, then the skipper can give 3EP's, and will probably choose to rank the top 3 MP's, and then give the last 9 guys unranked MP's.... if you are the #2MP, you are the #5 of 15 overall. Your last fitrep in the command when you depart is not ranked against anybody... you are ranked 1 of 1... it's the CO's last chance to convey to a selection board how good you are in case you depart a squdron in July, and the last time you were ranked against your peers was January... you might have been the AOPS for 6 months carrying the squadron on your shoulders, but since you're unable to be ranked against your peers, the CO will give you a #1EP of 1, and inside the writeup in your fitrep, he will say that you walked on water and are the second coming of Pappy Boyington.
During your career, you will have your FLYING JOB and your GROUND JOB. Your ground job as a JO can be in any department in a squadron. You will start out doing something that sucks and progress to the competitive hi-profile jobs. Your goal during a 3-year sea-tour is to have 3-4jobs. Some jobs by their nature you must hold longer than others. LEGAL Officers usually hold that position for a year or more... sending guys to legal school costs money and there is a long learning curve to get good at it. On the other hand, Public Affairs Officer or 1stLT is usually a short-term jobs just to get your feet wet that every new-guy must endure. To get out of a squadron with a strong #1 or #2 EP, you should try and hold one of the higher profile jobs for a decent amount of time. Assistant OPS, Quality Assurance Officer (QAO), and a few other jobs are big players when it comes time to rank guys.
One thing to remember when you're talking about your career is always to remember that you're an officer before you're an aviator. Quite often, an aviator will really suck, and the CO is not giving them the jobs or fitreps that will allow them to compete against their peers at a level needed to continue flying. Usually these people are oblivious to the fact that they suck or are in denial, and nobody will tell them... and they wonder why the detailer suddenly has no jobs a the RAG whenever they call. There are a lot of guys who after their JO tour, will never get in a plane again. This is not to say they're not good officers, just that maybe aviation isn't for them after all. If that guys is looking at completeing their JO tour at the 5year mark, and has 15yrs to go until retirement with zero chance of ever flying again... now what? Let's say the guy is a total rockstar but comes down with a blood condition or something else that NPQ's (not physically qualified) them from flying? Now what? There are plenty of other jobs that an avaitor can do with make LCDR and then put in their 20yrs... and a lot of different ways to go to get out of aviation and get another designator and have a full career as not-an-aviator.
But basically, if you want to be a CO of a squadron:
JO Tour: AOPS/QAO/Paddles with a 6+month #1 or 2 EP.
Shore Duty: RAG, Test, or WTI (VT's also play well in some communities)
Disassociated: Aide/ANAV/Shooter/CAGstaff/Super-JO/Test/Detailer
Mini-Tour Between Disassociated and DH (if your timing allows): War College
DH: OPSO or MO (need long ticket-punch 6-8mo+)
Second Shore: Joint, Pentagon, Aquisition, suckin' it on the big staff somewhere
XO/CO
There are few other ways to make CO/XO of a fleet squadron.
Sustained Superior Perforamance at Sea. Breakout fitreps (ranked MP's) follwed by top EP's well above the CO's average.
Somewhere near the end of your shore tour or very early in your disassociated, you'll need to think about staying in/out when the end of your commitment comes up. You can take the bonus and obligate yourself through your DH tour, drop your letter and get out, or do neither and take a chance on the Navy deciding they no longer need you. But the system is geared that there is really only one time that you can justify getting out prior to 20yrs, and that is at the end of your initial commitment as an aviator. If take the bonus and screen dor department head, you'll have over 14yrs before the next chance to get out comes... and nobody will stare retirement at 6 years away and throw in the towell.