HAI, this is LOLOLOLOLOLOLx here if you didn't realise I love fun champs who I can troll with.. But yah I've really enjoyed Hecarim and saw that no one was building him properly (in my opinion). hope you enjoy my first build and thumbs it up if it works for you ;).

Pro: very good early game ganks
High Mobility
Fast clear time around (3:30)
fairly Tanky with great late game initiations

Con: Item reliant to be tanky
Hard to master

Greater Quintessence of Swiftness: you need the bonus movement speed for clearing jungle faster, ganking lanes, and it works with your passive (I can get up to 150 extra damage with "homestay" boots amazing for protecting base.)

Greater Mark of Desolation: these runes work really well with Hecarim especially with his Q and E

Greater Glyph of Warding: Since season 3 defense has become even more important (because they increased the cost) due to that it's a great idea to build magic resist Glyphs.

Greater Seal of Resilience: (Armour :P)

Hecarims two core Items are "Frozen Fist" and "Spirt Visage" the main idea behind my build is how your able to be tanky and put out enough damage output that you cannot be ignored. Frozen Fist is awesome because gives Hecarim Armour and cool down reduction while having a neat passive of slowing the enemies, Spirt Visage gives hp and magic resist while increasing the effectiveness of your W (spirit of the dead)

Warpath
Hecarim ignores unit collision and gains attack damage equal to a percentage of his bonus movement speed. Warpath is a awesome passive, especially when defending base the damage you receive from Homestay boots at max speed doubles your attack damage.... (147-305)

Rampage
Hecarim cleaves nearby enemies for 50/85/120/155/190 (+0.4) physical damage. (66% damage to minions and monsters) When Hecarim hits nearby enemies with his Q the cool down is reduced by 1 second (stacks up to two times)

Spirit of Dread
Hecarim deals 80/125/170/215/260 (+0.8*AP) magic damage over 4 seconds to all nearby enemies. Hecarim is healed for 10/15/20/25/30% of the damage these enemies take from any source. This ability I always thought to be pretty useless but it was pointed out to me how important it is to your jungle sustain and clear time, as well as doing large amounts of aoe damage and heals you during team fights.

Devastating Charge
Hecarim gains increasing movement speed for 4 seconds. His next attack knocks the target back dealing 40/75/110/145/180 (+0.8) to 80/150/220/290/360 physical damage based on how far Hecarim has traveled during Devastating Charge. I love this ability, Increabily fun to use as well giving you a large speed boost for only 60mana, it can be used for getting around the jungle, catching up to fleeing enemies and a initiation for team fights.

Onslaught of Shadows
Hecarim summons spectral riders and charges forward, dealing 100/200/300 (+0.8*AP) magic damage to anyone they strike. Hecarim releases a shockwave when he finishes his charge dealing an additional 50/125/200 (+0.4*AP) magic damage and causing nearby enemies to flee from Hecarim for 1 seconds.
All I have to say amazing initiation for end game team fights I love this ability completely disrupts their whole team (can be used as a escape as well but it's better to use it in the team fight).

As Hecarim I find Farming is fairly easy, you can usually keep your cs equal to the rest of your team just by in the jungle just turning on your W and SMASHING your Q button.

Wolves -> Blue Buff -> Wraiths -> Wolves agian -> Red Buff -> Mini Golems

Make sure your allies damage the wraiths and Blue Buff or else you might have a bit of trouble clearing the jungle but if all goes well your clear time should be around 3:30 and be able to gank after that (only if you have enough hp otherwise go back to fountain then gank).

I hope my guide helps people play hecarim, I've seen so many bad Hecarims out there building phantom dancers. This was my first build so it's kinda ****py but thanks for reading up to here have fun charging around the map while shouting GO PARTY PONIE!!!!