Build and Runes
Avoid being clumped so he won’t be able to use his ultimate to fear multiple people.
Move away from him when he has his Spirit of Dread on, as he will heal from any source of damage dealth to enemies.
When an enemy Hecarim ganks your lane, do not allow him to go behind you while he has his ‘Devestating Charge’ movement speed buff active. He may knock you back slightly, away from your tower into the opposing laner, preventing you from getting saved.
To counter the power of Hecarim’s ganks pick exhaust or champions with stuns or slows. It will massively reduce effect of his passive and Devastating Charge.