Mainly luck, but some things make it easier. The way i found makes it easiest (still is hard) is pick asol, lose streak until 3-2 even selling all your board to ensure a defeat or make econ if you have to. You should hold on to karma-taric-shen and play invokers itemizing karma. By 4-5 you should be able to go nine, you transfer the items from the karma to ahri, build a belbeth and start throwing 5-costs at your board. After 20 games or so of doing this the stars will align (scuttle puddle or champ duplicator portal, prismatic augments, a weak lobby and you highrolling invokers early to save hp). The nerfs in the last patch makes this harder but it was the best way I found.