Why Malphite? - Malphite is a rock.. He hurts! Would you like a huge rock tossed at you hard enough that it sends you flying in the air?.. No I didn't think so.

Malphite is a lot of fun, he has a strong early game (his passive shield + regen pendent make it hard if not impossible to poke your health down) when you hit level 6 your ult is amazing to gain kills.

Even at low level your slow helps to get a first blood if the person you are with can do some burst.

Late game you have very high health and can easily initiate fights for your team and come out living because of your high health and with all this defence your high dmg (slam)

Pros

High health
Hard to get picked on early game
high defence(AD stacker's suck verse you)
High health .. you can take a pretty big beating.
Ult is beastly and will gain you main kills (or you can use it to escape a gank)

Cons

Slow
Wont do crazy amount of dmg late game (he hits really hard early game)
Magic dmg hurts you early game.. if you are faced with mages rush force of nature.

For the most part your priority is

R > Q > E > W

but get one of each by level 3.

R let you poke at people early game and slow them + increase your speed to chase for the kill.

Malphite is very mana starved and this helps make it bearable.. Don't let anyone tell you blue buff isn't for you. (take it!)
Flash or ghost will help get away/to someone in a fight.

With your shield and Regen pendent you shouldn't have to go back to base till you have like 2000 gold. Keep farming, get levelled passed everyone else and get some kills!

Im new to this guide thing, I hope this helped you, Please rate/comment on what needs to be added/improved, il take everything into consideration.