Before starting this build, Note that flat magic resist glyphs is the ones you should have, They didn't list them on the build list for Glyphs. I selected these runes for early game lane domination. With a dorans shield and these runes, you can harass and life steal your health back up very easily. Most ad champs will do severely reduced damage against you using these runes and dorans shield as a starter item.

Build one (with thornmail) is a build that is used for an AD heavy team with auto attack champs (yi, trynd, cait, etc.) Build Dorans shield first, boots (If you have a heavy CC champ in your lane and would like to purchase merc treads at once, go ahead) then a sheen, i like to buy a BF Sword before finishing the Trinity just for the extra damage and burst. Then complete the build as necessary, but i suggest to follow the build in steps as shown in purchase order. Unlike build two, this build doesn't offer any extra movement speed, but it does offer you the return damage on basic attacks for champs such as master yi, gangplank, and tryndamere (And any other ad carry you can think of). This allows you to deal extra damage to them, plus with your ignite cutting their life steal in half, you can really destroy ad carries using this build. Not only do you have the armor, but also health, which means you can sustain more of a beating. even in the few days since Hecarims release, you wouldn't believe the number of Master Yis i've melted using this build.

Build two is for a more AP heavy team, when you're up against Cass or heavy bursting late game AP champs. Follow build like build one. It will allow for more magic resist but will not have the thornmail for armor and return damage on basic attacks. This makes you more vulnerable for basic attackers such as master Yi and Tryndamere so be careful on which build and make sure to build according to their team comp. With this build you will also get more movement speed though. Which with Force of nature it isn't flat movement speed its scaling percent, which means when using devastating charge and ghost it will boost your speed and consequently your ad a bit also, using this to your advantage, late game you can gank faster, and hit harder, especially considering the scaling to your devastating charge increases with your range and speed.

When laning as hecarim, make sure to use your spirit of dread as a life stealing lifeline. You will be able to harass using your devastating charge, then using your rampage. the small stun after your devastating charge will allow you to get a basic attack and a rampage off before they can return the hit. using your speed and no unit collision you can easily get away after harassing the opponent. this doesn't work as well when harassing a ranged champ, so when doing so make sure to hit, do your damage, and use your spirit of dread as you're running away from them to life steal in case they do get some damage on you. With the runes and armor from start game, you should be able to get lane dominance against mostly any champion; as long as your lane mate assists. For best effect use Hecarim with a ranged champ or assist. Although not an AD carry, with this build Hecarim can surely pull some extra weight for the team.

For quick getaways after level 3, pop ghost then your devastating charge. With any sort of boots your movement speed will top at over 600. This is very effective for not only going into fights but getting away. This method can also be used for catching master Yi, as with boots at the end of your charge you will catch him. If necessary for catching him you might have to use your ult for the fear. Most of the time you will be able to catch him, and if using build number two, then late game after you build Force of nature, you will easily catch him because of your movement speed being over 700.

When ganking as Hecarim, make sure as you're approaching the nearest champion, to use ghost and devastating charge together to make a massive burst hit, then combine that with your spirit of dread and continuous use of rampage. Make sure to use both Rampage and Spirit of dread as soon as you're within rage of the champ. The enemy champion should begin to run away, position your ult over them but slightly in front of their path and use that, then continue using your rampage and ignite if necessary. This is most effective after building trinity force or sheen.

During team fights Hecarim is a very valuable tool. Initiate with your devastating charge, then ult into the main pack of enemy champs then use your spirit of dread and rampage. (if there is a noticeable pack and if your team is there. Remember, be smart with anything you do. Don't dive into a situation without your team backing you) then focus the Carries / squishies and continue to use rampage. If it is late game you should be a pretty good tank by now, and if it is early game make sure to watch your health. In any situation try not to sacrifice your self if not necessary. In a team fight your spirit of dread will be a very useful tool, as most team fights are over within a few seconds you will be able to use your spirit of dread for sustainability and damage (with this build towards level 10 it starts to hurt quite a bit)

This is the build i use on Hecarim. For me it has been VERY useful and effective in 5 v 5s. I decided to update this after I went 27/6/12 in the last game i played, and even in the few days since his release I have carried many more using this build. Thanks for taking the time to read this and I hope this guide has been as useful to you as it has been to me. If you wish to ask any questions or would like clarification for anything on the build, feel free to message me on here, or add me in league, Nickname SmasherOfPies