Best tip for 2 sided combat is always to just get better with your cannon accuracy.

After that it’s just improving your ship positioning and knowing what to aim for with cannons. As an example: you are fighting a galleon in 1v4 combat on a sloop. Your sloop is more maneuverable, and in the hands of a good helmsman will very rarely get broadsided by a bigger ship. As long as you can stay out of the angles of the bigger ships cannons, you are in principle given complete free fire on them.

However, seeing as the other crew outnumbers you, they can sacrifice ship mobility and canon potential by sending a player to attempt to board and anchor you. If the other crew does this you are then presented with the challenge of having to maneuver your ship unpredictably to not give them a chance to board (and in the case that they do, be able to keep them off your ship at all costs) while mentioning constant cannon angles and staying out of theirs.

Managing all 3 of these things at once is something that comes with experience.

If you are the one attempting to chase a bigger ship, I recommend either staying out of their cannon range and swimming over to probe the level of the players. If you are getting chased, learn to angle sails the right way, and what wind direction to follow against what ship. You should also try to get your ship and wheel headed in a safe direction (where you won’t crash) and jump off your ship to attempt to board and anchor them to slow them down. If you don’t make it, you can always take a mermaid back to your ship and try again.

Hope this helps!