So, apart from the obvious modification for increased FSD range, what other blueprints benefit jump distance?
Should I be going for every lightweight mod I can get my hands on?
Are there any blueprints where the random secondary effects benefit FSD range?
Is jump distance related only to optimised mass?
All of this can be looked up on Inara, but to save you time:
-Yes, lightweight your lifesupport, your weapons and your utilities. Depending on how many utility slots you have it can be more worthwile to take one heat sink and mod it to have more ammunition or two take two and lightweight them until they are light as feathers.
-Yes, low-power shields for example not only reduce power draw, they also make the shield generator lighter (and you get a small chance of making them a little bit stronger). This of course works best with a large, heavy ship because then you can take a large, heavy D-class generator and profit more from making it lighter.
-If you engineer your Power Distributor to be engine-based, your bonus to engine capacity and regen makes it so you can take a size smaller then normal and still boost. And boost more often then normal, even!
Jump distance is related to fuel usage, optimal mass and optimized mass: The higher the optimal mass rating is, the less fuel the ship uses and the farther it can jump. Fuel usage can be reduced by secondary FSD effects but has another side effect: Fuel tank size determines how much fuel you can use in a single jump. This is why making the tank smaller stops working after a while and instead of more range you suddenly
lose jump range: If the tank is too small you're suddenly unable to efficiently use your FSD.
This means if you get a secondary effect reducing fuel usage you get sometimes more jump range, or you can reduce your tank size further to squeeze more range out of the ship. (I don't recommend doing this, though. That way lies madness and the desolation of being stranded far from home.) Optimized mass if of course, only about making your ship lighter.
Or to make it shorter and less text-wally:
-FSD's optimal mass: More range if higher
-Ship's mass: More range if lower
-Fuel usage: More range if lower / plus more jumps