Runes.:

For Ram ram i go for magic resist /lvl marks and glyphs,dodge seals and quints.

Summoer spells.:
flash+ghost is a must have no other working options if you want to play it well

Skill levels.:
well if you play tower def,or just like to be defensive try level defensive ball first,but its a stupid way to play rammus.
if you serious max taunt and be aggressive you are really hard to kill even with 1 point in defensive ball at lvl 3
and dont forget you need only 1 point on powerball at lvl 1,until you cant spend it on anything else

Try always buy items against the enemy in the lane armor or mr,never rush for hp in the beginning. After you got the (assist?!) kill ofc and the tower. go back to shop,
WARNING the upcoming gear buy sequence is situational,dont fail.

vs a nicely balanced team you need the gear up there, for a successful armordillo:)

dont underestimate the power of thornmail+sunfire+defense ball, you going to do tons of damage

many ppl tell getting leviathan is stupid but you are NOT going to die, and as you reach 20 stack you are just unkillable,tryn is like a kittie clawing your back:)

Pros.:
- Fun to play
- Hardest to kill champion in the game
- Able to 1v1 any champ
- Best champ to save an ally in problem
- Fastest champion in the game really nice for chasing,running away(lol you dont rly need to run away)
- Towers please do damage

Cons.:
- manaregen could be a problem
- if defensive ball on cd you can be harmed

You are the god,the unkillable,undefeatable,if you want to intiate a teamfight rush in powerball,flash to the centre of their team, taunt the mostly feeded(highest dmg dealer)
activate defensiveball,and ulti
you make way more damage to dont get just ignored like mundo and this is what you want force them to attack you!
if you die your team did something wrong

as the team probably got a tower go and gank, hide in the bush activate your super fun powerball wait 5 seconds or so, activate ghost and try to "fly" behind the enemy with lighspeed.
Your goal is to moove between the enemy champion and their tower (this way he cant run away)
if enemy using flash,you do it too(but care to flash towards it so you knock him back)
taunt him.: now 2 options.:
if the target is melee stay and use defensive ball
if the target is too close to the tower(melee),or the target is ranged just run to your allie after the taunt
Pop ulti if you need the + dmg or the kill:),or just keep it for the tower
if your target is not dead, tell your allie to uninstall the game and play hello kitty online or tetris ect....