First off, what is a point leak? A point leak is basically a weakness in a target design (or perhaps intentional...) that allows you to get free event points with no damage, often with ships that are severely underpowered for the target. Old school raids were target oriented and like Campaigns and resource fleets, if you couldn't kill the entire target, it wasn't worth anything. Modern raid world map targets are now almost entirely point based, and you get what you kill.
An example of a point leak can be found in the lvl 111 Research Garrison Forsaken Mission target. As soon as you enter the target, there is a tiny platform to the right with one turret on it that as far as I can tell, does absolutely nothing. Killing it with literally ANYTHING, even Marauders, nets you 3750 FM points, more than a lvl 40 Research Garrison. You can wait for the Retreat button to light up and exit the target for the free points.
When a new raid comes up, work your way DOWN the levels of targets (bigger targets leak bigger points) with the smallest ship it will let you engage it with. I keep a Battle Barge A fleet around just for this purpose. When you enter a new target and the battle starts, immediately hit Up Arrow to select all your ships, then followed by Down Arrow to stop them from moving. Make sure nothing is already moving towards you or firing at you. That was a problem in old school targets but Kixeye has mellowed out on that a bit.
Once you can safely scroll around the the target, look around the perimeter for things that may be targets, but don't have any turrets on the side of them facing out. Kixeye has primarily kept to making the only the dangerous targets actually worth points, but sometimes slips up on this. A Shrike may be able to surface just within range of these and snipe them for free points. Other types of ships will need to find a way to these.
Whether or not you see any cheese left out in the wind, you'll still need to find where you can safely travel, and if there are any shorter range guns you can snipe without getting killed. Some of the ships in my BBa fleet have a Squall Launcher on each one just for this purpose. With a range of 94, it can probe around the perimeter for targets it can hit, and by slowly poking around and detecting (by getting killed...) longer range threats you can get an idea where you can attack for free. Other ships have a Pandemonium mortar with a range of 86, and find targets you can drop splash attacks on and see what effect this has on other, perhaps more valuable and dangerous targets. That smelter that you are raining mortars down onto may only be worth 47 pts, but the guns around it that are taking splash damage may be worth tens of thousands.
If the target has fleets, take very careful note of where your probe ship is when they are triggered and begin circling. When you actually hit the target you can set traps for the ships and strip them from the target instead of having them jump you by surprise later. Often ships are not worth very many points even though they present a threat because you CAN set traps for them and Kixeye stopped paying that off a while ago, but you can try it and see.
Sometimes after killing a gun by sniping or splashing it opens up other chances for free points. After you hit a weakness you detected, exit the target and send the probe fleet back in to see if you opened anything up.
Things to watch for:
1) Buildings near turrets, but facing closer to the outside where you can hit them with splash, UAV chaining, or shockwave damage without exposing yourself to the guns
2) Ships sitting around waiting to be attacked. Some don't move, but some can be drawn out with a bait ship and into traps. Take one of your probe ships with your trap fleet to use as bait.
3) Short range guns on the outer edge of the terrain. You may be able to kill these with Launchers or other very long range weapons
4) Otherwise dangerous targets that the Small Long Pinch rocket can affect. Most targets have anti-rocket turrets in them, but some don't.
5) Lather, Rinse, Repeat. If one of the above produces a result, try your probe fleet in that area again after killing the target(s), something else may have opened up.
Key tech to have:
1) A probe fleet consisting of instant repair ships with long range weapons.
2) Remote fire missile and/or mortar ships for setting traps. Proto-Mastodons, though very old, are one of the best remote fire missile ships. Remote fire mortar ships such as Citadels or Monoliths should have as much splash from as many different sources as you can fit on the ships. Remember, ALL SPLASH IS THE SAME, REGARDLESS OF SOURCE. Even though Narrow Firing Aperture is for Corrosive weapons, having it on a mortar ship still adds to your total splash % for any weapon that has a Splash attribute. Conversely, putting Combustion System II on a scattergun ship will also add even more splash to the scatterguns even though the special was intended for rockets or mortars. You will also need a very tough ship for the baited ships to attack when they get to your trap. Have a tiny ship of each fleet type loaded up with high level zero repair time armors to use as a bait ship.
These tactics are not only useful for finding free points, but learning how to pick apart seemingly impossible targets and killing them completely with minimum damage.