Q is the best skill to max for laning, as it provides damage, pushing power, and sustain. Max E after Q, followed by W. Obviously rank up your ultimate whenever it's available.
If you suspect the enemy jungler might "one buff" gank you, take E first. Q is much stronger at level 1, but E can make the difference between surviving a red buff gank and giving up first blood.
Proper Skill and Fury Usage:
When I describe a skill as having fury priority, I'm simply saying that that skill should be used with the Fury bonus over your other skills. Note that having a full Fury bar will allow you to cast 2 Fury empowered abilities, and I'll leave the 2nd decision up to personal judgement.
Cull of the Meek has fury priority in situations where you're trying to output the most AoE damage possible, e.g. teamfights, or when you need to heal in an engagement. If you're fighting in an enemy creep wave, its highly recommended you use this skill with fury.
Ruthless Predator has fury priority in 1v1 engagements where there are no enemy creeps available to heal off of. It's also good to use in teamfights to lock down a target for a longer period of time, but depending on how grouped the enemy team is, it doesn't necessarily take precedent over Q.
Generally my least fury prioritized skill, I only use 50 Fury on Slice and Dice when my team is AD heavy and I have the opportunity to dice through multiple targets. The fury bonuses on Q and W and just too good to pass up, leaving us with a skill that is hardly used with the fury bonus effect.
Although your ult doesn't gain any bonus effect with the use of Fury, take note that your ult grants you additional Fury gain, which allows a bit more forgiveness if you happen to use an ability with Fury when, in hindsight, it could have been used elsewhere.
Renekton's harass combo is fairly basic - dash in, harass, dash out. Of course, if you're going all in for a kill, you would dash forward again to stay on top of the enemy. This simple combo, however, is not the maximum damage you're capable of doing. Much like Riven, to get the most out of your skillset, mixing in autoattacks between every ability is what separates good players from great. An optimized combo would be as follows:
From this step-by-step process, we can identify the reasoning behind E having the least Fury priority in a combo. If you have 100 fury as you start your combo, you would dash in, autoattack, W, autoattack, Q, autoattack, and dash away. Since Fury is only consumed on the 2nd part of Slice and Dice, we would use 50 Fury on W and the other 50 on Q, leaving us with 0 to use on Dice.