So I couldn't find a guide to Hecarim on the forums that wasn't confusing to read. I'm not saying mine is good/OP/anything more than bad. A quick search will show you I'm currently stuck in Elo Hell (my own fault I guess, supports can't carry games D: ) but it's a guide to how I play him and hopefully will be easy to read and understand. And if you're completely new to Hecarim like I was and cbf'd playing him to learn how you like him, I hope this helps. My guide is to play as tank initiator hecarim, mostly for solo top lane.
Offence mastery point; Ignite/Exhaust SS spell.
Defence mastery points;
It's important to note you do not take the SS mastery in the defense tree. Instead you take the armour and MR masteries and max those. Then you max every mastery in the downwards row second from the left, also maxing Vigor.
Utility mastery points;
You can either max Good Hands or Expanded Mind, either or, and improved recall. Don't bother with the Clarvoyance/Flash SS mastery. Then max the bonus movement speed mastery points.
Usually I go ignite over exhuast. Why? Because if your opponent in top lane has heal, along with its recent nerf, you're going to counter them pretty hard. Also, if your opponent has skills that vamp life to them, a well timed ignite will put a stop to that and help you dominate them if you initiate at the right time.
Over flash? But flash is OP bro!!?!?!?!?
smart positioning (which I learnt through maining Ashe for a month or so) has taught me how to almost never use flash. In the circumstances I would use it, it's when it's a straight foot chase anyway, in which case the prolonged speed period of ghost is better. The 35% speed buff also procs with your passive so when your opponent realises he is going to lose a fight and tries to run, not only can you chase him/her down, but you get bonus AD also.
Marks - Flat AD or ArPen (depending on your play style
Glyphs - CDR (flat or per level, up to you. I like per level personally)
Marks - Armour
Quints - Move speed (no dur right?)
This is the main part that I needed to know when I started playing him.
Start boots and 3 pots.
Rather than purchasing anything else, upgrade your boots right away. Either to Merc Treads or Ninja Tabi depending on your opposition.
Then build a Heart of gold.
Somewhere inbetween your basic boots and finishing your heart of gold you want to be buying one pink ward and a green ward. Pink ward the river outside baron to see incoming ganks. Green ward which ever bush up top your opponent seems to like hiding in.
From heart of gold get a Zeal. The AS is nice, it builds into Trinity Force and the bonus movement speed gives you some AD (Not much, but enough to be useful this early on).
After zeal you need to think about your main opposition. Are they AP or AD? If your against an AD your gunna want to build into Randuins. If not, build into FoN. You will get both of them anyway, but early game you want to be situational depending on who your laning against. Which ever one you choose, buy just the main ingredient. For example, if you chose Randuins, get a Wardens mail. If you chose FoN, get the Negatron Cloak.
Once you have that item, build a Phage.
After phage you want to finish your Randuins/FoN.
Once you've finished that it's time to think again. Are you needing to be more defensive or can you go on the attack? If you're ready to go on the attack, finish off the Trinity Force. If not build a FoN/Randuins. What ever one you didn't get. Then finish off the Trinity.
At this point, you should look like this.
Merc Treads/Ninja Tabi
Next, build a Hex Drinker.
After this, build a Glacial Shroud
Then, finish off either a Maw of Mal or a Frozen Heart. Which ever comes first is up to you and your game. If your taking more AP dmg, do Maw first and vice versa.
If it's a gank, or a team fight you know you'll win, you want to initiate with your ultimate. The flee time on your enemies wil help your jungler/team get in on them, and help you to position for a knock back on a prime target with your E. Constantly swing your Q spell and keep your W up as much as you remember too.
Anyway, hope this was as easy to read as I think it was when I wrote it. Hope it's useful. And I hope it doesn't get too ripped apart by everyone out there who knows how to play this game to its mathematical meta.
Helpful criticism (be nice though) appreciated.