Hi this is Chris Huang and I'm a level 7 Darius player from NA server. My two main top laners Jayce & Darius got me to Gold in season 6 so I believe Darius is a perfect champion for solo queue. Btw sorry for my bad English XD, if there's anything you don't understand plz ask me at the discussion section, I will try my best to explain it.

Pros with this build

Insane early/mid game damage.
Huge threat to squishy carries.
Can turn around teamfights with ultimate reset.
High outplay potential.
Crazy sustain with

Decimate
Amazing movement speed(won't get kited and easier to dodge skillshots).
Fairly tanky.

Cons with this build

It takes time to adapt this fast-pace play style.
Damage falls off at late game.
Lack of gap closers, really relying on Flash.

Some people are confused about which skill to max after Decimate. Well, in my opinion, Crippling Strike and Apprehend are both really powerful. Crippling Strike is an auto attack modifier makes your last hit more smooth and also applies a 90% slow. I personally max Crippling Strike second if I was struggling and playing defensive. Otherwise max Apprehend since reduced cooldown and increased armor pen simply makes u more aggressive.

Basic Combos (laning)

1.Auto Attack,

Crippling Strike, Auto Attack, Auto Attack, Decimate, Apprehend
2. Apprehend, Auto Attack, Crippling Strike, Auto Attack, Decimate, Auto Attack

These two combos are the simple fastest and most effective ways to proc Noxian Might and Stormraider's Surge during laning phase.
There's one thing to to keep in mind, keep urself moving when AA, because of the Stormraider's Surge and Ghost, when orb-walking u can always outrun your enemies.

Advanced Combos (laning)
1. "Q Flash", Auto Attack, Crippling Strike, keep AA till your enemy used any dash abilities such as Safeguard / Iron Will, Apprehend, Decimate.
Make sure to leave a mastery 7 medal to their corpse :D.

Additional tips
Rapter Cloak is a powerful item which gives u valuable Movement Speed during chases and escapes
Darius' Crippling Strike can't damage Yorick's wall.

Teamfight is the hardest part in my opinion so I will explain this in details.

Split push strategy:
Split push if ur far ahead, u can easily 1v2 with both your summoner spells. Stop split pushing and join teamfights after u purchased the Z'z Rot Portal.

Engage timing:
Avoid getting into a team fight without your summoner spells, especially Ghost. Initiate a team fight with "Q Flash" combo is devastating, but also really risky, so consider carefully before all in.

During TF:
As Darius, u have two roles: Reaper and Frontline Tank. The most important thing in a team fight is to proc Noxian Might, find the nearest target if u don't have Flash to threat their backline, and quickly use the basic combos to get the Noxian Might. At this moment, immediately charge toward their carries, you're tanky enough to tank for CD's for another combo, remember: Hit as much people as u can with ur Decimate. This will proc full stacks of Hemorrhage to enemies which deals disgusting damage over time, especially to squishies, and finish them up with Noxian Guillotine. As soon as u successfully get a dunk, u will get a burst of speed due to the passive of Phage and Stormraider's Surge . And at this point this TF is over. Ez right XD?