I apologize if these builds are simple and there aren't more the two although Hecarim is a jungler or solo top lane if you know how to play him well. He is incredibly tanky as well as still being able to output a fair bit of damage. His Q or rampage ability is excellent for pushing lanes or killing jungle creeps due to its low cooldown and mana cost. His W or spirit of dread allows him decent sustain off minions although it caps at about 180 health off of minions however against enemy champions it has no limit allowing him to be incredibly sustainable in teamfights so long as your team and you are outputing damage. His E or devastating charge allows for excellent early game ganks or can act as an escape should the need arise. Hecarims ultimate Onslaught of Shadows allows for some soft cc and an amazing engagement tool also allows him to pass over walls and can act as a flash should the need arise. Finally Hecarims passive allows him to gain AD for his Bonus MS also it allows him to pass over minions without being blocked.

Hecarim is an AD champion so it is self explanatory that you take flat AD marks for the early game ganks. You can also take flat armor penetration marks for the early game damage.
Hecarims seals are flat armor in order to be able to jungle more efficiently at earlier levels.
Hecarims glyphs are flat magic resist which are my personal preference although it is more efficient to have per level MR glyphs.
Finally Hecarims Quints are MS quints whixch allows hecarim greater MS and AD due to his passive.

Taking all damage mastries allows hecarim to farm easier as well as kill jungle minions while also allowing for better early game ganks seeing as how late game he is a much better tank. The other points are put into defense in order to increase his sustainability.

On Hecarim it is best to open boots of speed 3 health potions this allows him to gank early as well as still being able to maintain your jungle. Then purchasing either 3 doran's blade or a wriggle's Lantern. After purchase a sheen leading into a trinity force. then purchasing a frozen mallet to become tankier and to not allow enemy champions to escape. Then purchasing either a randuins omen or warmorgs armor both allow for increased sustain ability as well as becoming much tankier. Then purchase a force of nature for the MR health regen and MS all which will greatly benefit hecarim. Finally finish the build with a atma's impaler you will have roughly 4000 health so it is a must on hecarim at that stage. (sorry for how disoriented this is i will update in the future to make this clearer and more detailed.)

Hecarims main damage output is his Q so it is best to max it out by level 9. His W allows for great sustain in team fights and while jungling so it is best to max by level 13. Hecarims E only requires one points as it acts as an escape or an initiation. Hecarims ultimate should be takin at 6, 11 and 16 for obvious reasons.

I chose smite and flash because hecarim requires smite in order to be able to jungle effectively and i chose flash because i think its the best summoner spell. Ghost is clearly a good option for hecarim as the MS bonus from ghost will also provide hecarim with increased attack damage. If your gon=ing solo top hecarim ignite and exhaust are good choices.

Hecarim excels at early game ganks and drops off late game to become a very tanky champion with moderate DPS. I apologize for how ****ty this guide is i will update in the near future in order to make a better and more detailed reasons to why i chose masteries runes etc.