I'm Went, a master tier rumble mid player, I first reached master tier with rumble top last season, however this season rumble top is too gankable and the removal of deathfire touch and the changes to his heat, makes him a lot weaker at setting up dives and pushing for early first tower which was his strength before. Also the matchups top lane are a lot harder now. Rumble mid is strong at early skirmishes, roaming, and teamfighting. I occasionally stream here https://www.twitch.tv/jussenk and my opgg is here http://na.op.gg/summoner/userName=went and here are some highlights Play Video

Q - Always max this first no matter what. The damage on flamespitter adds up very quickly, and this ability will be your best tool for shoving in waves and getting out to roam.

W - This is what helps you survive in mid lane, use this whenever you're about to get poked or whenever you engage for a trade, this will be the last ability you max.

E - Take this if you're against champions with high priority level 1 (ex. Talon, Aurelion Sol, ect.) This is the main way you will be procing Electrocute so it's important to get good at hitting these. When you start putting points into your E they will do disgusting damage. Max this 2nd.

R - Practicing with R is crucial for playing Rumble. Level 6 if the jungler ganks 9 times out of 10 you can turn around and 1 shot them. Rumble's ult also has extremely far range so you can engage a fight before you even get there. This is a huge game changer in teamfights so it's important to be good at picking where to place it most effectively and to make this decision very quickly.

Passive - It is important to manage your heat, being above 50 heat gives you 50% more damage on your Q and your E, it also makes your shield 50% stronger. Get your heat up and then keep it above 50 with your W. When you're sure you can get a kill use a full rotation and auto-attacks if you're in range, you can still use a second harpoon and overheating gives you bonus damage with auto attacks.

If your heat is too high when you engage you'll end up overheating too early and be locked out of your abilities for 5 seconds, so pay attention to your heat bar.

- Take flash 100% of games, theres not much else to be said about this.

- This is the most standard secondary summoner spell. Ignite gives you stronger 1v1 and 2v2 skirmish potentional. 1 tick of Ignite can also be used to proc Electrocute.

- If you're really uncomfortable playing against an assassin then you can take exhaust to keep yourself from feeding, but I would still always take Ignite over Exhaust.

- You really wont need teleport in mid lane, Rumble's W gives high mobility and will help you get back to lane quicker and roam fast. If you do take teleport then I suggest it only be in Top.

- Take Electrocute on Rumble mid because his strength is burst and early skirmishes. With Ignite and Electrocute up you can kill any jungler with one rotation if you get the jump on them.

- Taste of blood is for trading and sustain in lane and it synergizes well with dorans shield.

- Take nullifying orb into magic damage matchups and I would suggest gathering storm for all ad matchups. Nimbus cloak can also be a situational pick.

Start Dorans Shield or Dark seal if you are greedy. I usually always start dorans shield.

The sustain in lane is incredible and often times you will win lane by eating poke until the enemy is out of mana and then you can keep them trapped in lane while you have opportunities to roam or harass them.

On your first recall you want to buy sorc boots, it helps with avoiding ganks and roaming, and rumble really needs the magic pen. If you do not have enough gold buy dark seal and boots. Always buy a pink ward because you need vision on the enemy jungler. Ninja tabis are needed in some matchups like talon and zed, however for some matchups like yasuo they aren't required because you beat him 1v1 anyway. If the enemy has ad jungle and mid you might want to consider buying seekers armguard and tabis early, but only if you are not your teams primary source of damage.

After that you want to buy haunting guise then liandrys, then morellonomicon. If you are snowballing hard you can get mejais or deathcap, but if it is a close game you probably want deathcap.

If the enemy is stacking MR you will want to buy an early void staff.

In most range matchups you will have to start e and survive the earlygame poke. Once you are level 3 you can begin to trade, you want to get to 50 heat, then w and q while walking at them, then you can either poke with e's or turn around.
For melee matchups trading is a lot easier as you can overheat without getting exploited while trying to disengage. You just try to proc electrocute while overheating with q.

Try to work with your jungler to get vision, and if you notice you have priority of the lane start trying to get wards and roam after you have shoved the enemy in.

The easiest mistake I see rumble players doing comes from champion select. If you have 3 magic damage dealers on your team, don't even play out the game, just dodge, its honestly not worth it as rumble powerspikes early and mid game, and with the enemies rushing early mr your penetration won't be as strong and you will have to buy an early void, so in general those games aren't good to play.

For roaming, you can look for overextended lanes but also see if one of your lanes is slow pushing a large wave into the enemies tower, that is a great time to collapse and dive the enemy under tower.

Also incase you didn't already know, always stay above 50 heat and spam w on the way back to lane for the increased movespeed. Most matchups will be covered on my twitch channel.