Malzahar can Summon Voidlings by spamming abilities at spawn. This can be useful at beginning of game by using an ability to quickly decimate the enemy minions in your lane.
Be aware that Voidlings grant 12 Gold as bounty. If you die while having a Voidling summoned, the Voidling will die as well and also grant its bounty.
Never underestimate Call of the Void. It is extremely effective at turning team fights, both damaging, and silencing as many enemies as possible.
Call of the Void can turn a disadvantageous push from enemy team into a stalemate by spamming it on incoming enemy champions. Enemies who were damaged and silenced will think twice, or even retreat from the front due to the momentary vulnerability while the silence debuff is in place.
If there is an enemy who needs to cast his whole combo and escape with skill try to silence him after he is in range. He will be an easy target after it.
Casting Malefic Visions on an enemy minion that is about to die is a good way to farm minion kills or harass safely because of its chain reaction.
At rank 5, with about 100 ability power, it can completely kill both melee and caster minions at full health.
Malzahar will still gain gold and xp from anywhere on the map if Malefic Visions finishes off the minions. This is useful both to avoid being denied and to continue to farm aggressively all game long.
Leveling up Malefic Visions early in the game is a great way to harass enemy champions without using any mana. Simply cast it on a wave of minions near the enemy champion and auto-attack the infected minion until it spreads to the champion. This results in around 50 gold, almost no mana lost (you might have gained mana), and the enemy champion being out of 100-200 health. At rank 1 it takes 6 minion kills to fully refund the mana cost. At all other ranks it takes 5 minion kills to fully refund the mana cost.
Against a single target (champion), Malefic Visions is Malzahar's most mana-efficient damage ability even if it doesn't jump, and is his only harassment method that won't push his lane.
There is a bug where two nearby Malefic Visions will not both propagate. Try to avoid casting a second copy in big minion waves.
玛尔扎哈的Null Zone deals a percentage of the target's maximum health, meaning that late game Malzahar can deal tons of damage when multiple enemies stand on his Null Zone.
玛尔扎哈的Nether Grasp does not have to be used to kill an enemy, but can disable an enemy instead.
Null Zone is a great way of zoning enemies as they realize it takes away a percentage of their health.
Most of enemy carries or mages believe that they can kill Malzahar without much realitation and might be overconfident knowing that Malzahar has no escape technique.Malzahar is espetially potent against this as Nether Grasp will prevent any damage during the combo
Void Staff is a useful item, giving you a lot of magic penetration, allowing all your abilities to deal more damage. Also use items such as Sorcerer's Shoes and Haunting Guise. The magic resist reduction of Abyssal Scepter however is only effective if you are within close range of the enemy which is not recommended for a squishy mage like Malzahar.
Malzahar can be built as a pusher as well. With his Voidling, he is able to put out a considerable amount of damage on turrets. Don't be afraid to buy Lich Bane if you are feeling confident enough to push.
If you see one of your allies under the effect of Nether Grasp, you can stun or silence the enemy Malzahar out of the channeling and turn it into a 2v1 fight.
If you play as a tank, take care not to stand above Null Zone for too long or else the spell will devastate your health and can sometimes kill you if you're not too careful as it deals a percentage of your health.
Malefic Visions is Malzahar's main farming-tool and mana-sustain early game. If you purchase a source of health replenishment early and then always move next to a minion that has Malefic Visions on it, so that it jumps over to you and not to another minion, you can literally obliterate his entire early game, as he will gain significantly less farm.
When you manage to catch Malefic Visionsearly and prevent it from passing on to other units, this will also greatly reduce the mana-refund of that spell and he will find himself to be out of mana quickly. This hurts Malzahar especially much since all his spells have high mana cost, and investing in Mana-Regeneration while having very low farm will diminish his damage-output midgame.
Malzahar's only way to punish that before level 6 are Voidlings who will attack you if you have Malefic Visions. In that case, try to run to your own tower and let it kill the Voidling.
Keep in mind that you can only use this technique if you have some source of health sustain. Due to the low farm Malzahar gets, he will not be able to purchase much additional ability power; Malefic Visions's damage is still not neglectible.