Marks
Attack Damage -> It is one of two basic Marks AD's. The Attack Damage is simply good to champions like Renekton, and your skills will become extremely strong in the early game.

Armor Pen -> Another great Marks for AD's, there is not a difference, so choose what you prefer, I will put my opinion here. Runes of Attack Damage help you farm in early game and give good damage at this stage. However, Armor Pen over time becomes more important because of the armor that enemies are gaining lvl. But I prefer attack damage marks to dominate the enemy. Choose what you want.

Seals
Health -> This seals are good if you are not facing AD champions, because you will have more HP, which means endure more against AP Champions.

Magic Resist -> This guide is for vs. AP right ? So if you want more defense than health, you can choose this seal, but in Glyphs you already use Magic Resist, so choose your favorite

Glyphs
Magic Resist -> After some time thinking about these runes, I came to the conclusion that CDR is not just important for Renekton. Your damage is already high, but with masteries of 21/9 you do not have to endure much against opponents without will contain something for them. Here enters the MR runes. Against AP Top is fully recommended you use Magic Resist, never use rune Magic Resist per Level

Quints
Attack Damage -> As I said in Marks, Attack Damage to farm is very good, so I decided to put a bit in Quints, helping the early game to be stronger. One thing that greatly helps Quints AD being my favorite is to know that two of Armor Pen Marks equate to a Quint Armor Pen, while two AD does not equate to a Quint, causing AD Quints are better (Marks equivalent to 9 and AD)

List 1 - 21/9/0    Explanation: Renekton is a burster Off-Tank, but before that, he is a champion of early game, so he needs all the damage at the beginning in order to be useful in the end. With these masteries, you maximize your damage early, can kill or just dominate your opponents, giving you a great advantage.
  
List 2 - 9/21/0
    Explanation: More defensive page. Is not useful in many situations, but when you're facing another early game champion, it can be good to get some reductions of damage, especially if you know that your damage will not be too small to do this.

It's good to take "Q" first, to help you farm, second I take "W", because if the enemy tries to dive me at start of the game (yeah,some people try dive me before 10 minutes), i just stun him, and he dies to the tower. And later I take "E" to be offensive. Now i maximize "W" because he has more damage in early game than "Q" and "E". The second skill to maximize is "Q", because it is the second damage skill. The last skill to maximize, it's "E" because it is not too important to be offensive

Reign of Anger
Renekton gains Fury for every autoattack he makes. This Fury can empower his abilities with bonus effects. Additionally, Renekton gains bonus Fury when he is low on life.
Cull the Meek
Renekton swings his blade, dealing moderate physical damage to all targets around him and healing for a small portion of the damage dealt. If he has more than 50 Fury, his damage and heal are increased.
Renekton swings his blade, dealing 60/90/120/150/180 (+80% bonus Attack Damage) physical damage to nearby enemies and gains 5% of the damage dealt as Health (20% for champions), up to 50/75/100/125/150. Enemy champions heal for 4x as much.
50 Fury Bonus: Damage increased to 90/135/180/225/270 (+120% bonus Attack Damage). Heal percent increased to 10%, up to 150/225/300/375/450.
Cost: No Cost or 50 Fury
Range: 325
Notes Great skill, and its second biggest burst damage. It is perfect to have sustain in lane, and farm easily. When you are low on health, try to get 50% of fury and simply press Q near a creep wave and see your HP up enough to get to stay longer in lane.
Ruthless Predator
Renekton slashes his target twice, dealing moderate physical damage and stuns them for 0.75 seconds. If Renekton has more than 50 Fury, he slashes his target three times, dealing high physical damage and stuns them for 1.5 seconds.
Renekton's next attack strikes twice, dealing 150% Attack Damage physical damage (10/30/50/70/90 + 150% of his Attack Damage) and stuns for 0.75 seconds. Each hit applies on-hit effects.
50 Fury Bonus: Instead, Renekton attacks three times, dealing 225% Attack Damage physical damage (15/45/75/105/135 + 225% of his Attack Damage) and stuns his target for 1.5 seconds.
Cost: No Cost or 50 Fury
Range: Self
Notes Your skill with most damage in early game. It is with this damage that you will destroy the enemies. Furiously this skill will give MUCH damage, and you can win lanes just spamming this skill. Remember that she uses OnHit effects, in other words, items like Black Cleaver, Wits End, Madreds Bloodrazor have very high damage with this skill.
Slice and Dice
Renekton dashes, dealing damage to units along the way. Empowered, Renekton deals bonus damage and reduces the armor of units hit.
Slice: Renekton dashes, dealing 30/60/90/120/150 (+90% bonus Attack Damage) physical damage. Hitting an enemy grants the ability to use Dice for 4 seconds.
Dice: Renekton dashes, dealing 30/60/90/120/150 (+90% bonus Attack Damage) physical damage.
Dice - 50 Fury Bonus: Damage increased to 45/90/135/180/225 (+135% bonus Attack Damage). Enemies hit have 15/20/25/30/35% reduced Armor for 4 seconds.
Cost: No Cost or 50 Fury
Range: 450
Notes This skill will save your life. Movement, harass, chase, escape, farm, you can do it all with this skill. Know how to use it in early will make you dominate the lane, so watch out.
Dominus
Renekton transforms into the Tyrant form, gaining bonus Health and dealing damage to enemies around him. While in this form, Renekton gains Fury periodically.
Renekton surrounds himself with dark energies for 15 seconds, gaining 300/450/600 Health. While active, he deals 40/70/100 (+10% Ability Power) magic damage to nearby enemies and gains 5 Fury per second.
Notes Skill without cost that will make Team Fights and small duels be your. The bonus HP will make you endure more damage, and the extra damage is not to throw away the fury you gain will make you just spamming skills with full damage almost all the time.
Sometimes, when I'm in trouble I use Ultimate to gain some life to escape from enemies. It always works. Other times when an enemy is less than half the life I use Ultimate and punch him under his tower. Always works too.

Now, the combo.
E into the enemy + W to stun and damage + Q to damage + E to get out.