You can also shut down unnecessary functions in your ship like the shield generator and boosters and weps and such to reduce your fuel usage, I think.
Yes, but that's not really a solution for when you still have range to get you to a system with a station, or if you have a scoop, a scoopable star.
Disabling modules will reduce drain from your reserve tank (thin line), so yes, that would need to recharge from your main tank (thick line) less frequently, but no, that's not going to make a noticeable difference to jump range. Hyperpace jumps use fuel from the main tank.
When a stranded player calls the Fuel Rats, as long as they are not on emergency oxygen, they will be coached to disable unnecessary modules. This is to extend the duration of their power to their life support, giving the Rats time to locate the player, go through the necessary winging up procedure, and arrive on scene. After delivering fuel, we will advise the player to re-enable their modules, and will observe that occurring to ensure the player is safe again.
If you realise you care getting caught short with not enough fuel to complete your journey, you might consider a diversion to a nearer system that has a station (or if you have a scoop, has a scoopable star. But if that is't possible - re-plotting using economical routing may well extend your fuel range enough to make the difference.
Added later: One caveat here....... The Fuel Rats get a noticeable number of calls to new commanders who get lured by a tasty high paying mission (or by misdirection), in their sidewinder, to Hutton Orbital station in Alpha Centurai (not knowing about the extreme travel time required to reach the station). The small fuel capacity of the sidewinder, normally means they run out of fuel on the long supercruise. IF you find yourself in a situation like that, Disabling modules (Leaving Life support, thrusters, and Frame shift drive on, but disabling power to everything else that you can, might be a valid survival tactic, and might extend your SC range sufficiently to reach the station as long as you realise and do it early enough.