This is my normal game setup i do when i play Rumble. If you are playing Rumble remember u get tanky without buying too much defense items. Rumble should be used to dominate the mid/late game whit the tankish item build and the great damage output.

I go whit magic pen red, armor yellow, ap blue and also ap quin.
I use this setup because i need to be tanky to get rlly close to get all my spells of and to do maximum damage whit my normal attks/spells.

As u can see my items have lot of MR witch means that i lack in armor and thats why i go armor yellow.

I go for maxing my E first but take 2 detours first in lvl 3 when i pick W instead of E just because i need the shield and extra movement speed the W gives. and the second one in lvl 9 when i pick Q instead of E just because in lvl 9 rumble start to get rlly good u might even gotten yourself some kills by then. And u start to get tanky so u can stay in fights longer witch means that ur Q will start to do more damage just because u can stay closer to the enemy for longer times and thats why i pick Q over E.

U should be careful in the laning phase even tho you are a bit tanky in lvl 1 u still die easy and u do not deal that much damage in lvl 1. my advice is stay back and use E whenever u can get a shot of at the enemy ore to get creep kills if the enemy is pushing you of the creeps. Once u hit lvl 4 u can start to go in and deal lot more damage in less time meaning this is when u can start to get kills if you are good whit the E spell.

Note: Remember if you are facing a lane whit loads of stuns ore just crowd control spells you want to put more points in Q earlier just because a stun ore a cc docent stop the Q spell if you already started it then it will finish no mater what.

In the team fights you can use the ulti to stop the enemy from ruining away ore from chasing you by placing the ulti ether behind them ore in front of them. If u neater of the teams want to escape ore if your team needs more damage to win the fight then just smash the ulti down in the middle of the team and they will separate to each side of the ulti and u can more easily pick them all of without any problems.

You can send me questions to my lol user name Pernus on EU West.
If you wish for more parts ore a more detailed guide i will release that later when i have time to write it ;)