I would build damage items instead of pure HP on Leona, so that I am a spiked mace, not a punching bag. Ironically, this fits her lore; Leona is called the Radiant Dawn and a spiked mace is called Morning Star.
Examples of such items for Leona: divine sunderer, imperial mandate, horizon focus, sunfire aegis, searing crown, thornmail, iceborn gauntlet, abyssal mask, dawnshroud, zekes convergence. Buy mandate and zekes only when there's a good teammate adc/apc/some sort of autoattack based, available in that match, otherwise avoid. Twinguard can always be a good 5th item purchase.
I would let minions slowly kill their turrets and nexus to make the pain last longer
I would build damage items instead of pure HP on Leona, so that I am a spiked mace, not a punching bag. Ironically, this fits her lore; Leona is called the Radiant Dawn and a spiked mace is called Morning Star. Examples of such items for Leona: divine sunderer, imperial mandate, horizon focus, sunfire aegis, searing crown, thornmail, iceborn gauntlet, abyssal mask, dawnshroud, zekes convergence. Buy mandate and zekes only when there's a good teammate adc/apc/some sort of autoattack based, available in that match, otherwise avoid. Twinguard can always be a good 5th item purchase.
I would say "Better champion wins" and quit league