it depends on the champion you face, you don't vounter it with items, but with how you play.
Atleast thats the idea, but depending on the matchup, it's not always possible...
However, looking at raw numbers, %truedamage isn't as bad as most people make it up to be, if you play a squishy, no-truedamage often hurts far more.
Gnar for example deals 50+14% with his W every 3 hits, compared to vaynes 60+8%, you need like 80 mr to break even, which is quite an investment on squishy champs like talon or ashe, especially vs a champ that deals mostly physical damage....
oeiole complain that they can't do shit vs %truedamage, but don't get the numbers are rather low.
For vayne to kill you with W-damage allone, she'd need ~33 AAs(depending on the targets max health because og the flat damage part), now guess how much % of your health in physical damage would be...
Fiora isn't strong because of her %truedamage, she's strong because of her low cd Q+E, doing huge physical damage, applying lifesteal to all of it, beeing sticky and haveing 0.75sec of invulnerbilliy+cc-immunity...