It's a Darius favored matchup. Be aware of his placement of his W and track when it goes off CD.
When his W is on CD is what allows you to kill him in the laning phase

When he ults you, put your e in the opposite position of where he ulted you from so you can grab him the moment he pops out from his ult and interrupt his burst combo.

An item concept a lot of people aren't aware of is buying amour into lethality users. Armor counters lethality users and negates majority of their damage