Seriously, I try AP/Tank, flat out AP, flat out Tank with high armor and mag. resist, and I've even tried building all this ridiculous amount of AD because fuck it, Malphite
is a difficult champ to build with. How do people make a build for this Champion that at least works?
How do you build malphite? However the fuck you want! He is rock solid.
i usually pick up a 
to help with laning and trading plus it helps your w passive and gives a nice mana pool and some aoe slows to help peel. after that i rush a 
for a big hp boost and armor ramp, if possible ill grab a 
if were going even it gives hp and mana over time keeping you tanky and relevant as you build 
and for boots i grab 
for ad heavy comps or 
for cc heavy comps so i can keep in the fight and lay down cc, the last item is purely player preferance as you could get ap items to hit harder, health items to be alive even longer or ar/mr items to tanky reduce more damage
pick up a rock and draw a face on it. boom baby malphite :D
honestly adapt to situations. you can build almost anything on him depending on how the teams look like and how the game goes, which position you play and if you snowball/dont.
I wrote a short article about this.
From his passive to his ultimate, Malphite has: % Max Health "Flat" movement speed % Armor
Meaning you want to maximize on HP, Armor, and % based movement speed.
If you need Tank Malphite, you should rely on his rather significant HP and Armor Ratios (if you're playing Draft, try not to pick him into Magic Damage teams if you need a Tank). If you need DPS Malphite, build CDR, Armor, AP, and % based Penetration If you need Burst Malphite, emphasize on AP, Flat Penetration, and some Armor.
You can tell which form of Malphite you want to build based on the damage triangle. If you need to counter a Burst Champion, build Tank. If you need to counter a Tank, build DPS. If you need to counter a DPS, build Burst.
some of the utility items are good on him, some arent, generally speaking you want to avoid picking in ap heavy comps ( 2 or more mages, such as 
or 
support with any of the meta midlane mages or top lane mages) as has very little durability against anything dealing magic damage, while you can build heavy mr to counter ap heavy teams, you will notice yourself being blowup very fast by ad carries as your lower armor wont negate them from fight as much as it normally would, as for what aoe items you should look to using on it comes down to what your looking for to make yourself have more presence.
If you want a more in-depth breakdown of some of these items see below, if not dont read on, sorry its a longer reply i try to give as much info as possible.
is great for helping the mages in your team hit harder and the mr resist helps survive a bit longer from burst mages, but lacks health increase, and if expensive if your behind.
and 
help wave clear and provide nice portions of armor which helps your W and health which increases your passive shield. but might set you back too much on gold if you team isnt enough ahead or need some different utility than what this provides
/
is great if your support or jng dont buy it and the enemy team has a mage, the boost it provides are all great on you and Banner gives strong pushing power if the enemy has a lot of mages as the minion boost makes them immune to magic. but thse can be very poor choces is the enemy has mostly ad champs as mr is not gonna stop a 
or
and are great for in general as they give a huge armor boost, one give slightly less armor for some huge hp, both slow attackspeed which when combined with you E basically you stop ad champs from hitting anything for a few seconds, and the slow from Omen makes for more peeling if your team gets dived frequently. always great on and are usually purchased on him regardless of the team comp (safe for the rogue all ap teams popping up as of late)
as stated this provides everything you need (baring health), big mana pool, aoe slow on ability casts, more damage, armor, cooldowns very potent if purchased.
is very strong for you if your team is relying on you to initiate a team fight, certain teams are only gonna have one initiator and if thats you grab this, if they have someone else who can initiate for you consider gettin this if you want x2 the fights, otherwise opt for more damage or tank items, as this might play against you as it hurts your laning phase and trading abilities.
