a few pointers. boots are essential, buy them on everyone, and the recommended boots aren't always right. usually you'd take berserker greaves on ranged carries and mercury's treads or ninja tabi, depending on the enemy team. if they're all attack damage, take ninja tabi for the physical damage reduction. if they have a great amount of stuns, slows, snares, etc. take mercury's treads for the tenacity, which makes them last 35% less (though, don't buy other tenacity items like cloak and dagger, or the others which i don't know because i've never had to use them, because they don't stack)