I'm almost two months old in this game, and now focusing in tiers 5-7. Love playing dd's even in this meta, though I want to be good in the three balanced classes: cruisers, destroyers and battleships. From tier 5 onwards you get better AA, and more than that you get better dd's which can distract the enemy cv and with luck survive until the cv gets exposed in late game, when its allies are sunk and the cv has overextended into spotting range. I want to practice until over 1.000 battles in this range of tier (now i have only 600+ in random) because later radar is really important to know, and I'm not confident enough in my ability in the basics to do the next task which is memorize radar ships and their radar's duration and range.
My advice is, progress faster in the lines you like most, and play more in the classes you like (I have 50% dd games, the rest goes 25% each in cruiser and bb). Try every line of every nation though, so you get the widest range of experience, so you learn faster the basics: look the minimap, shoot while free viewing - re-aim -shoot while freeviewing, always know where your rudder is taking you, know how to angle and when it won't save you (overmatch is scary), when to cap, know when you will start overextending, knowing the health of your allies so you don't end up alone in 10 seconds and you're wondering how is it that you were just fine and now are overextended. CV's though overpowered, are a pest that shouldn't spoil the game, as it is nonetheless rich in challenges that you can actually overcome.
You can also look forward to dive in a 8-9-9 division to snipe and kill enemy cv's: you get two mates with a Musashi each, and you drive your planes of a fast planes' cv (Graf Zeppelin, Shokaku or Indomitable) into the spawn place of the enemy cv, and snipe them in 3 minutes in.
And sell your ships only until tier 4 inclusive, so you don't suffer more from their bad AA. I'm keeping my 5's, 6's and 7's ships, and taking the captains on the higher tier ship of each line to get them to 19 points some day.
This game has strong unbalans, but it's constant chant of "git gud" can with some effort and love make one get really good and enjoy the process.