Early game you want to hit lvl 2 first in lane and immediately go for a kill with q+w+ignite. The hail of blades rune will make this easier, as the attack speed will allow you to win the early 1v1. Focus on farming and rushing your first item, titanic hydra. Because Skaarl counts as bonus health, the item will give about +60 ad along with 500 health and cleave, allowing Kled to consistently push wave to tower and roam to other lanes with his ultimate.

After titanic hydra, roaming to other lanes is how you will carry your team to victory. The bonus ad and hail of blades stacks with his w, allowing Kled to have amazing burst with his w, and his q,e, and r will give him maximum stickiness to ensure his combo kills his target. This is when HOB Kled is at his strongest so play very aggressive in all lanes.

In teamfights, HOB Kled is both an assassin and engage for his team. Ult into teamfights, but instead of fighting front-to-back, use your e+q to burst the enemy's backline. You most likely will be bursted down, however that is okay. Try to get at least one enemy before getting dismounted. Once dismounted, finish off any low health enemies and back off until triumph restores health and assists bring back courage. If you can't make it out and are targeted, you most likely still will have taken down their adc, putting them at an overall disadvantage.

HOB Kled falls off even more so than normal kled, in the sense that because he has traded tankiness for burst damage, he can't really serve as a tank for his team, and will most likely be killed after he ults into teamfights. You just have to hope that your ganks were enough for your team to pick up the pace as HOB kled falls behind.

After the Hydra powerspike, the sky's the limit for what boots you can get. Berserker's greaves work for getting out his burst faster, however in a losing matchup armor/magic resist boots can be viable (depending on how the opposing mid-laner does damage). Duskblade of Draktharr offers more burst along with invisibility after kills, which is essential for Kled to avoid the enemy team from bursting him. The Collector is yet more burst damage, and the passive is good for both staying ahead of the enemy and finishing off low targets with his dismounted q. His last item is Ghostblade, which helps Kled chase/escape when dismounted with reduced movement speed. The last item is a free space for whichever works best with both team's comp. Sterak's gage is a placeholder I put in because it is just really good in general and is never the "wrong" option.