What is F2P?

Do not worry about Expert and Veteran, first improve the level to drive BB5 (if you are a BB player), so you can get more attacks to get more exp. Even if you don't have a lot of Expert , you can still get more damage with a BB like Nelson/ Lion1 /Lion2-more experience than a QE with more Expert and Veteran.

I'd just go for play as much as possible in BB.
something a lot of people do is start 2 bo's, since you need to level up extra supports and most nations have 2 bb lines at some point.

leveling a 2nd bo will give you an insight in the lines you can play and which playstyle you prefer (nelson vs vanguard i believe).
it will also make sure your gunners (& supports)are several lvls ahead of your bo's, which will increase the accuracy & rep+eng.

basically what is wrong is people gain to much xp to easily, back in the day it would take me a year to get to a bb6, the smaller the server population got the more xp events we get to keep attracting players. but with extra xp boosts you dont gain extra experts. so there's an inbalance in the game nowadays that creates your problem.
(i believe i usually had about 70 vets and 100-150 experts by the time i got out of blitz, without spending any money, but with spending a lot of extra games to get there)
so you could say that you are actually experiencing a luxury problem ^^


Make sure you only convert experts to vets during events, no point in wasting them with bad %


The rangemarkers on BO's used to reach the shellspots by mid BB3 if i recall correctly, but with the above situation i'm not sure if that still goes. so it's normal to not spot them early on, i wouldnt do to much about it, because later on you will have to downsize the lines to fit your ships. (so dont waste money on bo's unless you get to 90-100 and still dont have the right lines)

The more red sailors you have the better odds you have to gain experts in battle.
With this in mind I always convert my experts when my sailors are below 50 vets even if there isnt a event goin on.  At those low numbers of vets, convertion rate is kinda OKish.

When you sailors have 99 vets you can still ad a 10 vets pack to it to get it to 109 vets. 

Most imported is to get your SD up to 900 asap I think while not using a restorder offcourse.

As flaggelant said, 2 BO lines at once improves enjoyment alot while grinding UK.

All the suggestions above are good except that you should not convert expert to vet (roll for vet) without the +vet conversion event.  With the current +500% vet conversion event, the first 40 expert to vet (from 0 vet to 40 vet) are almost automatic (close to 100% success rate even without premium account).  Then, the success rate decreases to around 1 to 5 ratio (20% success rate without premium) between 40 and 80 vet.  If you do the math, it is cheaper to purchase experts and convert them to vet during this +500% event for below 80 vet.  The chance continues to decrease at above 80 vet.  This is the time to use vet item (between 80 vet to 109 vet).  At high sailor levels (high total number of sailors) and high number of vet (e.g., 200+ vet), it becomes more difficult even with the event (e.g., rolling 400 experts for 10 vet).  You can do the math to see the difference between with and without the +500% event.  Make sure that NF GM has turned the +500% feature on before rolling.  I lost some experts (unexpected failing rate) this and last events because the GM forgot to turn on the event on Sat.  Also, it is probability (by chance), so you can get more or less vet than the success rates I mentioned above, so beware.