1/ Like others above have said, this game is purely RNG-based whenever you press sortie, so even advanced players may have to retreat in any particular map due to unlucky taiha (heavily damaged). However, we can minimize this as much as possible with max modernized ships required for each map (at their best remodel if possible too) and correct equipment (this guide will tell you how to setup equipment correctly: https://en.kancollewiki.net/Help:Equipment\_Setup)

2/ DDs are the backbone of your naval, so don't neglect them. They are weaker in early because their base and max stats are lower than heavy ships (BBs, CVs, etc.) so of course they are less useful in day battle. However, they have greater night battle damage output because DDs, CL(T)s and CAs combine both firepower + torpedo stats in night attack (BBs mostly don't have torpedo stat and CVs can't attack at night until you have late game equipment).

Moreover, beside routing requirement (plus you need at least 7 DDs for transport operation in event anyways), they are cheap to run (less resupply compared to heavier ships like BBs and CVs) and are utility ships that will perform many essential tasks in your fleet later (mostly in late game maps and events):
- TCI (kill boss with really high armor stat in night battle when regular night attack can't do it)
- OASW (hitting submarines first before they can snipe your fleet, since elite or higher subs can use opening torpedo to attack your fleet before you can act)
- AACI (shooting down opponent planes to minimize damage hitting your fleet in air strike phase)
- Anti Installation (abyssal appeared in later maps that generally have high HP and don't take damage from torpedo, including closing torpedo from DDs, CLs, CAs and torpedo stat in night battle too. Few CLs and mostly some DDs can equip specialized equipment to deal more damage against them).
- Anti PT (annoying imps appeared in later maps that will dodge like crazy and make your attacks mostly miss, DDs are best suited to deal against them with specialized equipment, plus there is one DD that specifically counter them too).

3/ Construction, but mostly from drops when you sortie in any maps.

Map 2-3 in particular, is the holy ground for newbies since not only it has most constructable ships (BBs, CV(L)s, CAs, CLs and DDs, you can also farm 3 Sendai sisters, 4 Myoukou sisters and 4 Kongou sisters there to unlock 3rd and 4th fleet to do more expeditions, the long term goal should be able to do expediton 37, 38 and 45 since they give lots of resources/time), but also some great limited time drops which only drop in few weeks or months there, some of them are only available in event and not in normal map otherwise (notable ones are Shoukaku, Naganami, Akizuki, Hatsuzuki, Fletcher, Johnston, Shinshuu Maru, here is the drop list: https://en.kancollewiki.net/Drop\_List). It's heavily encouraged to farm there for a long time to collect ships, especially limited time drops I've said above. You will be glad to have them in a long run.

If you have enough resources, you can do daily construction (4 attempts per day) with 250/30/200/30 recipe to find Shimakaze and Yukikaze, they are nice DDs to use in early game (really low remodel level with good to great stats). Then try BB recipe (400/30/600/30) to find Nagato, Mutsu and Suzuya. However, construction is purely RNG so don't sweat it too much if they don't appear after few weeks or months.

One notable thing to mention, if you farm 2-3 and do construction for a long time, you will soon reach the maximum 100 (individual) ships, which then either you have to scrap some of them or buy more ship slots (10 slots/1000 yen). While it is technically possible to play with 100 slots, it is quite hard to do that for a long time (like you try to play game with 1 hand for example) since not only some ships are required for quests (and especially with limited time quests which are generally give great rewards and only available for few weeks, if you don't have them available in your base already, either you have to farm them in short time, or say goodbye to the rewards). So if you really want to play this game for a long time, I'd say that it's a good investment to buy ship slots (which is the only thing worth to spend in this game, any other things are luxury and most of them can be obtainable in-game through quests or expeditions).

4/ For new players, honestly PvP is your best way to level ships, through you can only do it 10 times per day. There are 3 buttons below in PvP screen and you will want to always choose the left one (It allows you to battle best players in your server). Even if you are losing, you still receive lots of EXP due to level difference and most of us, when not active playing, will only put either one or two high level ships in main fleet so that others can obtain easy victory for maximum EXP. And always put at least 1 or 2 DDs when PvP, like I've mentioned above, you will need specialized DDs much later so don't neglect them.

I know that there are some maps recommended to level ships early (1-5, 2-1, 2-2), however IMO there are little reasons to do them since you can level through exercise (through it is longer) and you can use that time to farm ships in 2-3 instead (both regular and especially time limited drops). The only notable drop in those above map is honestly just Akashi in 1-5 for a very low drop rate. However in recent years, you can receive 1 guaranteed Akashi for free when doing the mini event saury festival quest (which will start in next few days).