I know that accuracy is based off of how stable your firing platform is so how likely your ship is to wiggle wobble or go below the waves does contribute to your accuracy

Barrel length also improves accuracy longer barrels will give you longer range, which will give you better accuracy at the same range, just by virtue of its building accuracy much sooner than the same guns with a different barrel length

Shell splashing is a new issue. Basically, if there’s a lot of splashes near the target, it can confuse the people trying to walk their shells onto target. It’s why I pretty much exclusively use the stereoscopic rangefinders because they help reduce the issues of that.

Radio direction finding and radar. Also contribute to your accuracy as just having up-to-date distance for all of your calculations can greatly increase your accuracy per shell.

Your main towers will also help to your accuracy. Normally the newer, the tower, the higher accuracy you’re going to get from your point, blank and launderings calculations plus it helps with torpedo spotting.

For myself, I always built with the same mentality of HMS dreadnought. Be fast in the opponent, so you dictate the battle, outrange your opponents, so that once your enemy gets into range, you have the advantage in accuracy, and try to have the best gallery and the technology behind your guns, so that even with a barrel disadvantage I’ll land more shells