An overview for a strong laning Renekton with 40% CDR. Basic ideas are in still under construction.
Standard skill path Q is wave clear, poke, and sustain. It is the best skill to max first and having it to start can set you up to push to lvl 2 fast and take lane control early. I prefer to level E first to lower the cooldown. This is your escape and main engage ability, a lower cooldown means more chances to trade. So, it's better utility vs. more burst damage. Leveling W second will give more burst damage on your trade and better all-in potential. Level your R when you can as per the usual.
Try to push early to get to level 2 first so you can use that advantage to get some good trades in and control the lane. If you can get that early level 2 with full rage, you can get a pretty strong trade that will make it hard for your opponent to recover. Make sure to get wards and keep vision of the gank paths. Hold your E for escape when the enemy jungler is in position to come top for a gank. Otherwise, keep pressure on your lane to deny farm and hopefully get a good lead with CS and/or kills. If you're strong you can get some 1v2 wins against the laner and jungler if they don't have much CC or burst, just have to not get caught off guard.
Keep the snowball rolling by pushing objectives. Use your burst to lock down and kill the enemy back line. If you're behind you'll have to rely on the carries for damage and do what you can to keep them alive.
This Renekton build focuses on utilizing the early game power to win lane and hopefully allow you to snowball the dominance into the other lanes. Keeping up on farm is key so you can burst down the enemies threats mid game in team fights and leave your team in a good position to win the fight.