I checked it out, you must bind it in keybindings / targeting. I didn't notice any difference so I checked it out on google.
https://robertsspaceindustries.com/community/citizen-spotlight/1850-Look-Ahead-Mode-Is-The-New-Default-Is-It-Any-Good-13
Look ahead mode only has effect when flying gimballed with mouse. Look ahead off: if you fly straight, then you can aim without turning your ship. Look ahead on: if you fly straight and aim with your mouse, then your ship also will turn to your mouse pointer.
I always fly with strafe. With NPCs you can go head on, when in firing range you start to strafe to the safe side (the side without asteroids or enemies) thus avoiding direct fire while keeping your guns in the right direction. Keep your aim slightly in from or on your target. Your target will fly into your bullets. If you make a tight enough strafing circle then you will end up at your targets tail. When doing this manoeuvre on a wave of multiple targets, be sure to pick the last target of the wave, otherwise you will have one or more targets on your tail.
Roll also gives you a better hitting chance, unless you fly the Vanguard with all guns concentrated on your nose. Your fire always will go on a parallel course, no convergence zone
Best hit chance is when your wings are parallel to your targets cross section, your targets flight direction.