Hi!
This is my first Guide on MobaFire, hope youll like it.

Ive mained Rumble since he was released and I think hes really strong. I usually dominate my lane and now im gonna teach you how!

You should go either Top lane or Mid lane. Laning against a melee champ is really easy. You can easily her*** with your Flamespitter. Laning against a ranged caster with a snare is on the other hand rather hard. For example Morgana.
You should play defensive and farm untill lvl 4 or 5. When you reach lvl 5 you should start to play agressive. Go close to the enemy and start usng your Flamespitter. Use your W (shield) to block DMG and increase your movement speed. When theres no minions between you and your enemy start using your E (Slowing harpoons). Make sure to hit both of them. Now you should have 60+ heat and youll have Mega slow and Uber DMG. Use your ultimate in their path if you have it.

I start off with Boots of Speed and 3 Health Potions.
On my first trip back i buy Hextech Revolve] and one or two Sight wards
Then i get Mercury's Treads and after that Rylai's Crystal Scepter
I buy Rabadon's Deathcap if i get fed
Abbyssal Scepter or Zhonya's Hourglas] if i need defence
I usually end my build with Void Staff if the game last that long
You can finish Will of the Ancients when it suits you

I start with either Flamespitter or Harpoons first. the reason beeing that Flamespitter does barely any damage at all and your harpoons has slow. So get your Harpoons first if youre doing a Lvl 1 fight.
Always lvl up your FLamespitter first becouse of its awsome damage. Get Shield or harpoons at lvl 2. Shield if you just want to farm. Harpoons if your jungler is ganking before lvl 4.

Reds: Magic pen

Yellows: armor, less damage from minions and champs. this is also good if youre laning against an AP champ becouse you will take minion hits.

Blues: i prefer Magic resistance per lvl. you can also use flat Magic resistant, Flap AP or AP/lvl. Only use AP runes if youre laning against a AD champ.

Quintessnce: I prefer flat AP but you can also use Movement speed or health

Flash is a MUST
Exhaust is very usefull before you get Rylai's
Ingite is good for all solo top champs.