First of all: Be in a airport with alot of demand.
Second: Use cheap (fuel drinking) Aircrafts there is alot of on the used marked.
Third: Use thoose cheap planes to earn money to expand more with cheap planes.
Next step : Buy New "good" Aircrafts with your earned money and change out your fleet before fuel start to rise to much.
But most important, DONT HAVE A LIFE, JOB & GF.... be online 24/7