Countering Hecarim

Hecarim really isn't special imo. He's got a fairly predictable ult.

Okay here we go.

Hecarim is an early game champion in the same vein as Lee Sin or Pantheon. He's strong as he's building up to Trinity Force, is a monster until about the 20 minute mark, then falls way the fuck off as his itemization and scaling doesn't scale well into the mid to late game. He seems powerful at every stage of the game because he's probably got a good lead, so you gotta shut him down there.

Hecarim's favorite route is the Predator/Krugs route, characterized by starting Red, clearing both Raptors and Krugs (the order of which naming the route, and who he wants to gank) before either going straight into a gank or recalling to pick up Blue Buff. For this reason, it's imperative to place down a ward on his Raptors to see what his game plan is. At the same time, ask one of your teammates to get a ward on his Blue, or keep a close eye as to who on the enemy team leashes for Hecarim. Anyway assuming he starts Red, you can use the Raptor ward to tell who he's gonna gank first. If he shows up on Raptors right away, the Side Lane is in danger. If there's a long delay before he shows up on Raptors, Mid is in the most danger. Warn your teammates based on who you think he's gonna gank. If for whatever reason Hecarim starts at Blue, he'll be doing a standard Blue/Wolves/Raptors/Red clear, giving your teammates more time and still making it really obvious what side of the map Hecarim will be on once he hits his Lv3.

Going by your name, I'm gonna go out on a limb here and say you're a Shaco player. As a Level 2 Jungler who can jump the Dragon/Baron pit, you can easily steal his Blue since Hecarim takes forever to get to it anyway. If you see an opportunity to cheese a gank, beware that Hecarim may just go ahead and steal your Blue now that you've revealed yourself, so plan around that (and steal his Blue as well anyway). At this point, the two of you are going to initiate vertical Jungling. For the first 5 minutes of the game, you have complete control of one side of the map while Hecarim has the other. I am going to be frank here, I think Hecarim has the edge over Shaco in a purely symmetrical vertical Jungling scenario, as I see his ganks as far more reliable than yours. Either way, use vertical Jungling to its greatest strengths and abuse free ganks on the side lane if they appear to be profitable while keeping a close eye on Mid and if Hecarim shows up. If you want to step on Hecarim's toes, it's going to be there.

Jungle Monsters respawn just before the 5 minute mark. Because of Hecarim's first clear, it tends to make his angles of attack come from his Red Buff part of the Jungle, where his Raptors and Krugs respawned. This makes it a little easier to predict what Hecarim wants to do, or at the very least where you should ward to keep an eye on him. The next set should show up around the 7:30 mark, though as the game progresses this rule of thumb gets blurrier and blurrier so keep it in mind but don't overly rely on it.

Shaco is a particularly bad matchup into Hecarim since Hecarim does the early game snowball thing far more reliably and he will build tanky as the game progresses, leaving one less easy target for Shaco. However, once you understand Hecarim's angles of attack and how his early route leaves his Blue Buff side of the Jungle free to just take, you can start to brick his early game. After that, it's only a matter of time and hoping you don't have that one laner that wants to feed the pony.

First you need superior reflexes, and aim with CC, or use champion, that has non-skillshot CC. And you need this on every lane.

Second: deep ward. Warding the river's bush is not enough, if you are pushed. By the time you can react his coming you are too late. So either no pushing, or ward deep. You only need 2 or 3 ward up at all times.

Third: Get heal reduction by midgame. You seriously need to counter his self heal in midgame.

Last: In midgame focus him with every CC you got, and pray, that you can beat the enemy without those CC.