What determines a plane's range?
As also stated in this answer:

Range is a function of MTOW and empty weight, according to the Breguet Equation for a jet:
$$R=\frac{V}{c_T} \cdot \frac{L}{D} \cdot ln\frac{W_i}{W_i-W_f}$$

with ${c_T}$ = specific fuel consumption, $W_i$ = initial weight, $W_f$ = fuel weight, $L$ = lift, $D$ = drag.

What increases range if other factors remain constant:


Higher speed $V$
Lower specific fuel consumption.
Higher lift/drag ratio.
Higher TakeOff/Landing weight ratio.


The weight ratio can be because of fuel weight used during the flight, but of course chucking ballast overboard helps as well.