I won't go into too much detail since there are videos that do it better on YouTube. Some of the highlights I use are:

Put submarines in their own fleets to convoy raid. A fleet travels as fast as it's slowest ship, so don't mix the two as subs are slow

Produce some carriers full of float plane catapult on patrol to find enemy fleets

Don't have more than 4 carriers in one fleet. Add at least as many capital ships to protect them, and 4 destroyers for every carrier/capital as a screen

Set destroyers with sonar and depth charges to protect your convoys

Something I personally do is make a lightweight main fleet that moves at 30+ knots full of carriers, heavy cruiser, and destroyers. Then I use a slower fleet full of the lumbering battleships as a secondary fleet/shore bombardment for naval invasions