This is my first guide so dont be to rough on the comments, but i would love some constructive crittisizm. I play Malzahar a decent amount along with other casters/dpser's. I like playing malzahar simply because he can do a lot of damage initially, he can silence, aoe damage abilities, and his ultimate stuns the target while raping them (much like Warwick's, but from ranged). But lets start off small on how i build him up to be the purple rape machine he is.

[*] Meki Pendant
I start with a pendant because it give you extra mana regen so i can i stay in lane longer. I spam my Malefic visions on minions because it will transfer from one to the next, thus giving you more gold so more rape.
[*] Tear of Goddess
This gives you more mana and mana regen, making you be able to stay in your lane longer.
[*] Sorcerer's Shoes
The +2 movement speed is nice, but also a 20 magic penetration is thrown on top to make your Nether Grasp do that much more damage.
[*] Mejia's Soul Stealer
This item can be one that makes or breaks a game for me, i always try to rush this if im confident i wont have to hug tower often in mid, and will be able to win most risks i take. The Item is a really OP item if you can get your stacks up quick, plus you get the 15% Cooldown reduction at 20 stacks. If my opponent in mid is durable and i cant harass them enough to kill them, or side laners keep tryin to gank, i dont worry about this item and get a void staff instead.
[*] Archangel's Staff
This is a great item for Malzahar because it helps you build up more mana and more Ap while casting abilities.
[*] Rabadon's Deathcap
This is the item that after you get it, you'll start to really hurt enemy's (not that you wont be already)
[*] Zhonya's Hourglass
One of Malz's biggest problems as a champion is his weak escaping abilities, Zhonya's helps you "freeze" your self from death and can really get you out of some tight spots like if your chased behind turret, in a specific enemy champ's ult, etc.

Pro's
-Ranged
-Mage
-Stunner
-Silencer
-Aoe
-Support

Con's
-Squishy
-Poor Escaper
-Not very good at chasing
-runs out of mana early game fast

As Malzahar i always try to grab Mid Lane since it has fastest monster rate, and you gain all experience. Malzahar can have a very strong farming method when you know how to use him right. I always use malefic visions on a smaller minion, while also auto-attacking it. when the enemy trys to get close i usually try to harass with call of the void, or if Malefic visions is off CD.

Teleport
I use teleport since im squishy and have to heal a lot, i can get back to my tower quickly.

Flash
Weak escaping skills=dead Malzahar. Flash helps you get away from enemy, or in other cases catch up to them.

1v1
-I try to harass with call of the void and malefic visions till about half healthish. then i'll try to pop malefic visions one more time and null zone under them, and then use nethergrasp on them while stunned on my null zone.

Team Fights
-During team fights i'll usually use call of the void to silence and take out a chunk of health, or just harass with null zone and malefic visions. Try to stay away from using Nether Grasp while in team fights since enemy's will usually try to single you out when doin this, try to be in the back of your team so your not as targeted as much during team fights.

Since your in mid 90% of your matches, its only fair if you go and help side lanes with ganking often, also making some kills and assists are nice too. When ganking pick the side thats being pushed back more to help them out. i usually hide in a bush and use call of the void to silence them then malefic visions and if your teamates are good you can usually get the job done.

Thanks for reading over my build, try it out before rating or commenting, but please do, down below..