[fruitfulbobcat]

Any Azur Lane fans here? I just started. Any tips?

[TheEnzo]

Sure! Retrofit ships are very rewarding to level up, you can filter by them in your dock. 
They have an additional skill tree you'll need to fill out to open up their locked potential. 
They can become some of the strongest ships in the game. 

Keep going until you unlock a Hard Mode stage past Map 3. 
Then play the crap out of it (3 times a day) until it becomes "Safe". 
This will let you skip to the boss of the map. 

Then doing the Hard Map 3 times a day gets you 3 cubes a day. 
It adds up fast, along with anything you come across with commissions. 

The only thing I really spent money on in the game is opening up my Dorm to its full 1st floor slots. 
This allowed me to train a full fleet without being logged in.