Azir is overall a very well-rounded mid laner. Azir has very safe poke early game and late game Azir becomes a beast in outputting so much damage constantly to a lot of enemies thanks to his soldiers. This is a short - compact guide on how I play Azir.

Pros - very relevant in team fights, safe laning phase. Can dish out tons of damage to lots of enemies constantly.

Cons - Squishy, little difficult,

Flash is the best
I use barrier most of the times. There are times when can be better, but as an Azir you can really see when you will be able to kill someone. Also, since Azir has fast attackspeed = later game your one shot with a soldier can do as much as ignite. So waiting on damage over time to kill something, your w or q can deal more damage quicker.
I used to use this few times, however barrier is still better imo.

I think barrier is one of the best spells for Azir, because when you end up engaging in an all in 1v1 with your lane opponent, often times, mid-laners have bursty damage which you can negate with your barrier and hopefully your soldiers are on top of your enemy allowing you to freely attack while the enemy has to wait for skill cool downs. - e.g if all ins you, try to keep one soldier at her 'w' and one near you. So after her initial burst is down and you have successfully defended against that using barrier, now its your turn to continuously damage her and secure a kill. Azir has hard time against champions that gets up close to him. Fizz, Zed, are difficult but you can barrier when you couldn't dodge their spells and otherwise might kill you. After their initial engage is over and are near you, you can then ult them and finish them.

could be useful for twistedfate

Azir is very weak at level 1. I often times do not even use 'w'. Because even in early levels, Azir has a good wave clear with his well placed soldiers dealing damage to multiple creeps, I try to last hit only for the first 1 or 2 waves. I focus hard on taking all the cs and not even bother about trade, especially if the enemy is a ranged champion. (If you are laning against zed, diana, fizz or other melee champions then you could try and throw in few auto attacks, however its important that you do not get too much aggro from the minions - so its best to farm till lvl 2-3)

At level 2 you can effectively harass your opponent with W + Q combo and trigger Thunderlord's Decree. Even at early levels, you can 100% hit the enemy at least 3 times.
Watch out for enemy champion's motion when going for cs, then get your W and hit once, and if the champion moves out of range you can use Q to follow up, hit second time and apply slow then bam! a third hit with Thunderlord. Because Azir gets very mana dependent, I try to just slowly deal damage using this combo. So after the first Thunderlord proc, continue to farm safely using auto for last hits and wait for Thunderlord cd then try for another combo if the enemy gets in range.

So during the entire early laning phase, you will barely need to use your E.
So I keep it in my pocket when a jungler comes up. If you get ganked, try to use the E to back however try not to collide with the enemy as it will stop you from moving the maximum distance. So unless the jungler comes up behind you it is pretty easy to avoid the gank.

If you are against , you have to use your E to effectively trade against her W. (her q+w combo). If is very good, she will try to get close + deal damage with her W then q+e you. If you have been hit by this combo, depending on your hp and hers, you either fight her with your soldiers + barrier or you might want to w+e away from her.
Azir vs LB is a skill match. However, knowing few tricks really helps.

Back to laning phase.
After level 6, you should feel much more safe. Now you can ult to disengage and w+e+q to dash back to your tower safely. What I have experienced is that often time, Azir's long range poke can really earn Azir a great advantage to push the lane and rush for tower.

Against very poking champions like , oriana, ,
Azir might have harder time to lane with. Since my guide does not build mana, you would want your jungler to feed you blue buff. When I am up against a pokey champs, I try to take cs thats close to me and keep the distance. Hopefully I can dodge their initial poke, then when I know their ability is on cd, I walk up and try for w+q combo to trigger thunderlords.
If you cant get close for W without taking too much damage then just try to farm our and hit them with q. Because once you have your 2 core items and , you can effectively hit 5 times. <- I'll talk about this in the next chapter.

Now you got both Nashor's Tooth and Rylai's Crystal Scepters.

It's your time to shine.

I don't go for mana items because I believe you really don't need it. Try to farm without using too much spells and make the most out of your spells; i.e, when you put down a soldier, make sure it can hit the enemy champion. so, you use mana = dealing damage for sure.

When you have acquired both attack speed + slow, now with your W, you can hit the enemy champion at least 2 times before him/her going out of range, then you follow with your Q and hit him few more times. It depends on your attack speed + level, but even with these two items, if you havent fallen way behind, you can chunk enemy mid or adc a third of their hp.
With Zonya or Rabadon, you can get to 50% of enemies health and the slow grants your teammates to easily follow up for a kill.