Renekton is very annoying to go against. 1 because he has god like sustain. 2 He'll be sustaining while slapping you silly. While playing as renekton you should almost always be poking your enemy with your 50 fury Q (you should always be farming while doing this of course) After you level 3 you should be able to use your combo, (unless they counter picked you then just play safe)[while you have 50+ fury] E in once (minions or enemy) Q W then E out to safety. This combo will not only take down your enemy's health but its a very safe trade since your 50 fury Q will regen health making you on top of your trade. Play Video

Mid to Late game is where renekton will get less damage and less sustain but that doesn't mean you can't be the tanky beast he is. Renekton is NOT a split pusher. Compared to Tryndamere you should almost never split push unless everyone is dead and you have nothing else to do. The reason you should never do this is because 1. You've built all tanky for a reason 2. You may have good mobility but that might not be enough to escape 3. You don't have enough damage to 2 v 1. With renekton you should always stay with your team mates in team fights. You should be the engager and the one who tanks the damage. (dont engage at a stupid time, just be patient and catch our the adc or ap mid) After early game you're not much of a damage dealer anymore, you're goal is to soak up damage and if lucky stun their carry

Late Game is where you should be the guy that takes 5 to kill. If by the end of team fights you survive with 2/3+ of your health while your adc and Mid dead, then you're not doing your job as a tank