please note that This guide is still in progress.
Hello this is my guide how to win with malphite im not a pro player but i have some experience with malphite hope you enjoy ;)

Pros

+ Good Tank/Support
+ Attack speed slow from Ground Slam
+ Movement speed steal from Seismic Shard
+ Shield every 10 secounds
Which scales with hp
+ 110% HP !!!!
+ effective trader
+ lucky with shamrock malphite !
+ high escape ability
+ Op mid and late game

Cons

- No chance in fights early game
- Highly poked early game
- Needs to be properly played with his Unstoppable Force
- Needs to be build into armor to have dmg (or maybe ap but he cant be so tanky)
- Mana Trouble early game
- Hard to trade against some champions
- Not enough continual damage output (combo and then he cant really do anything)

For Masteries i have went 0/27/3 Getting all the tankyness that i can Physical Damage reduction magic resistance , Bonus hp and Shorter Slows etc And the 3 Other points Went to Meditation becouse as i have said malphite has mana trouble early game so he needs some mana regen but these 3 points could be given in Wanderer for some extra movement out of battle.

First i would talk about my runes why i have picked them and what different choices do you have following my build.

Marks

For marks i have chosen Greater Mark of Magic Penetration as every malphites ability is from magic damage this means that you will ignore some of your enemies % magic resitance which means more damages and more damages are goood !.Other runes are actually useless like for example Greater Mark of Ability Power gives you only 0.50 ap per runes which is actually useless and Greater Mark of Attack Damage and greater mark of armor penetration is actually useless as you mostly got nothing ad and if you have some, you have no attack speed and thats the problem :/ so yep Greater Mark of Magic Penetration is probably the best pick.

Seals

For seals i have got just Greater Seal of Armor which is standard tank runes these runes give you huge boost to your armor and more armor of course means less damage from physical damage ability's and auto attacks [%] Also if you are going to the jungle the monsters will deal less damage to you.If you are finding that you actually need more hp becouse of the build you are doing feel free to take Greater Seal of Health or Greater Seal of Scaling Health if you are getting tons of hp and think that you cant do anything with it you are wrong you can take Greater Seal of Percent Health which give you health depending on your current health So More hp = EVEN MORE HP dont really recommend taking those but if you want you can.Also its not really usefull to take Greater Seal of Health if it gives you like 50 hp [all of the runes together] which is mostly nothing i would rather have like 12 more armor or take Greater Seal of Scaling Health about 250 hp [together too] at lvl 18 thats better.

Glyphs

For glyphs i have got Greater Glyph of Magic Resist which is standard for a tank a good boost to magic resistance But if you are going ap malphite and want more damage you can take Greater Glyph of Ability Power or Greater Glyph of Magic Penetration for more ap or more penetration if your opponent is tanky.Also if you would like more magic resistance but you have a ad top for example you can take Greater Glyph of Scaling Magic Resist which will give you magic resistance per lvl and on lvl 18 the scaling magic resistance runes have 2x bigger effect than the normal ones oh and as i said malphite has really big mana trouble early game thats why we take philosopher's stone but if you find that its not enough mana regen you can take Greater Glyph of Mana Regeneration they dont give you too much but if you want them.

Masteries should be mainly Flash and Exhaust as you need the instant teleport that Flash gives you and slow and damage reduction from Exhaust remember that it also reduces the healing effects for fiddlestick for example.
The exhaust could be swamped with Ghost for extra mobility or Ignite for finishing off summoners and getting this bit of damage remember that Ignite counters Heal but does not counter Barrier