Oh, and remember to not mix and match weapon types and speeds on your turrets.
The AI is actually much better at leading shots than any player I've seen, but since it fires all of it's weapon computers at the same time, it can get confused by weapons with different travel times. For example, a cannon shot takes time to fly out and hit a target, a beam hits it instantly. So the cannon has to fire in front of where the target is going (lead the shot) to make sure it hits, while a beam has to be fired straight at it. A turret with a cannon and a beam won't know where to aim because those two targeting strategies conflict.
So if you're going to mix and match weapons on a single turret, try to make sure that their method of travel (instant vs. delayed) and the travel time of the projectile match.
Weapon Systems - StarMade Wiki
So you could mix a cannon with a cannon/cannon on one turret and it will be fine, they both have a projectile speed of 10x ship speed. Mixing Cannon/Cannon with Missile/Cannon would be bad, because the missiles travel at ~6x speed, and hence need a larger lead to hit.
Related note, the speed at which a projectile travels (cannon bullets, missiles, etc) is based on the maximum speed of the ship firing it. The slower the ship, the slower the projectiles. For turrets, it doesn't mean much, the AI compensates by leading the shot more. For manual fire, it means a titan has to shoot farther ahead of the target than a fighter with the same setup does.
Also means titan missiles are slow as christmas, and slow missiles are easier to shoot down with point defense.
Missile/Pulse might give you the highest damage per shot, and being a smart missile means you don't have to worry about the aim, but it travels at 2/3rds the max speed of your ship. Which pretty much means anything can outrun it if it tries. On a big slow titan, you could practically outrun the thing with a brisk jog in astronaut mode. :p
Final note, all combinations for a given weapon work out to the exact same DPS and power requirements, so there is no "strongest combination" overall. A combination that does 10x the damage costs 10x the energy up front to fire, and takes 10x longer to reload, so it all balances out.
But there is a hidden tradeoff. Big damage combinations (like X/Pulse) suck huge amounts of energy up front, meaning you need large banks of capacitors to hold the charge for them. Fast combinations (like X/Cannon) cost almost nothing per shot in energy, and hence can mostly draw from raw energy per second generation of the ship.
Which basically makes Missile/Pulse pretty worthless, IMO. Only the slowest of ships will be able to afford the power to fire it in the first place, and it will be so ungodly slow that unless you are firing off near server breaking amounts of decoy missiles, there's just no way in hell the pulse missile shot will connect if they have any PDTs left at all.