darius is a lane bully who exceeds by extended trades due to passive and ult execute. he is immobile use this to your advantage. if you are going melee into him its harder. he is a juggernaut designed to be slow, have little to no cc/engage but will kill you if he gets ahold of you. play safe early, dodge bait his Q its main trade tool, sustain and farming tool. he also uses it to start most all in/combos. so kite, keep distance, dont go for extended trades, out sustain. if you get out of laning phase with out dying and equal in cs and have a scaling champ or a better team fight champ he gets out classed unless fed. i alot of the times start with dorans shield for sustain or boots to keep away from him. he does alot of true damage/bleed so building hp is effective vs him some what more so then start armor cuz of has passive on E that gives him armor pen.
as far as the match up i play the most vs darius is maokai but im a one trick and typically maokai is suppose to hard lose the lane vs him but i rarely do cuz of things i described plus as maokai i dont have to win lane per say to be effective in mid game/ team fights