Malzahar is a AP nuker and he does a great damage over time
you have too have a quick thinking when you use skills or escaping
because malzahar doesnt have any escaping move thats why you get rylai crystal and flash

For runes i get abilty power seal & quintenssence and magic penetration for mark & glyph
you need lost of ap for malzahar because malzahars ultimate nether grasp is plus 1.5 abilyt power which deals a lot of damage late game.

for masteries i raise 9/0/21

for items i get mejai sousltealer soon as possible to get lots of stacks by assisting and killing
and socerers boots for magic pen , dorans ring at the start for health and mana regen , after mejai i get rylai soon as possible so even though u get gankes you can slow them down , you have more health and it is a good item for malzahar.
Rabadon's dethscap gives you a crazy amount of Abilty Power which makes u r ultiamte unbeatable
void staff gives u alot of amount of abilty power and magic pen
will of the ancients gives u good amount of abilty power and good spell vamp so when you use ulti is almost like fiddles drain

malzahar's skill combo is Q,E,W,ignite,R it is the best combo for squishy chracters is almost 1 hit k.o u have to think fast not slow FAST ! BETCHES !! gash ...
and for summoner spells i get ignite and flash , Flash for escpaing fights , ignite for the skill combo. goes well with Malefic Visions