Build Guide by Railen

First blood
Start yourself out with a longsword for a little extra bite. You are going to try to get first blood and usually your best opportunity is at lvl 2, If you are in a 2v1 lane, you and your partner should be able to both be at lvl 2 with the solo enemy, if its a 2v2 lane try to target the squishy, Basically you enable your q skill, charge them, then hit them until they get tossed in the air, MAYBE 1 more hit pending on your partner, ignite them and GTFO, Make sure you don't over commit you are fairly squishy yourself but if you do this correct you should be fine.
If you are left with little or no health after your first blood you have 2 choices, bp back, buy a fort pot and go for a couple more ganks, or you can pop your health potion auto attack some creeps to get some health back and try to work a lvl advantage, Both options are solid and some are better against certain opponents.

If you choose to stay in the lane after first blood try to not go back until you can atleast get the recurve bow, and maybe the recurve+boots.

Mid Game
Your job is to initiate ganks and murder squishies, you will want to get a pickaxe or a BF sword as your first component of the Infinity edge because you will need the extra bite. In Team fights you want to stand just a little back (or walk into the fight rather then using your charge and saving that to jump on the positioning enemy squishy) and as soon as you see that Enemy Nuker about to drop his load you jump all over his **** and make him deal with you (which usually involves running away from you). After you finish your Infinity Edge its time to think about a defensive Item. Depending on the opposing team composition, Banshee's Veil, Aegis, and Guardian Angel are all solid choices, as is the ever popular and effective Randuins Omen.

Late Game
By late game you should be picking up 1200-1300 bang for your buck items, and buying Elixers. Pick up a Zeal, grab a green and red elixer. Because at this stage if you lose a team fight you can lose the game outright. If the game seems to be dragging on build your Zeal into a Phantom Dancer, if it goes on a very long time build a bloodthirster. The game should not go on that long.