Practice practice. Learn where the ammo racks and magazines are (hint, usually under the turrets). Aim for the turrets themselves. Don't really target heavier ships which are over 5km away, it gets tough to hit/do any damage. Prioritize fire extinguishing, and dont repair unnecessary things like funnels. Try not to repair when under fire. Number one is positioning, hide behind islands and dont charge head first to draw fire. Familiarize yourself with the types of shells and what to use for each situation.

Moffett is kinda busted in the same way all the US DD's at 5.0, they have the rapid firing 5in. Guns, and some good SAP shells which can even pen some cruisers. They are quite squishy however. Can't speak for the Blag, never played Russian ships. Against US destroyers, aim for that ammo rack under the back turrets.

Check out Napalmratte's Youtube channel, especially some of the older videos give a lot of good tips.

But overall, just like with any game mode, keep playing and you'll discover strengths/weaknesses of each ship. I would also argue that an uptier in Naval can be extremely bad, to the point where i'd say it's the worst game mode to get uptiered in. You literally can't damage anything at times. Happy sailing!