Hi there,
This guide is for those of us who love to split push, slow, poison and most importantly get away from our enemies...

The key points to this guide are; movement speed, Attack speed and Attack damage. The key points to this are explained below

PLEASE REMEMBER THIS GUIDE HAS ALMOST NO DURABILITY TO SURVIVE AND DO WELL YOU MUST RUN FROM YOUR ENEMIES, USING BLINDS YOUR NATURAL MS (MOVE QUICK!) AND YOUR MUSHROOMS!
COVER YOUR BACK WITH VISION OF THE MAP!

The above build that I have given you is one I use. It maximises AS and Ms with a little AD.

Other options are out there..

The bloodthirster for a little more AD
A Frozen Mallet for Slows (which works well with your Runann's)
or a Nashor's Tooth, for some more Ap and CDR

But I find that the above build rules all. For the purposes of this guide

So above you can see I've done the classic of maxing Toxic Shot first, followed by Move Quick, then Blinding Dart (taking a point in Noxious Trap Whenever Available)

THE ABOVE IS A VAGUE GUIDE... You Must edit it to fit your current game... For example;

If I am playing a quick melee player, who is always chasing me and IS QUICKER THEN ME. I take early points in Blinding Dart... This is to allow me to escape unhurt.. He will chase and continue to slash at me... but all his attacks will miss. This is to help you survive until under tower.

If I am playing someone with a high damage output, but is the SAME SPEED (or similar) as me. I will Take early Points in Move Quick... This means I can out pace him, either back to tower or forcing him to give up the chase.

If I am playing a tanky champion or a lazy champion, who does not chase me much. I use the Skill Structure in my guide. Where i sit back and Harass whilst being sure to last hit.

Laning / Early Game

Here you want to be farming in the middle of your lane, not so close to your tower that you lose CS and not to far that you can't run back and hide under it...

Pre Mushrooms;

Your main objective is to poke and annoy your opponent, so they either hang back and miss out on CS OR Don't realise its happening and you pick up easy kills/ they burn through their potions OR they start making stupid decisions.

You want to really get under their skin. You can do this by;
1) If they chase you and give up. Make sure you chase them back away from your tower! Always punish them coming to far forward, a blind and a few poison darts and they regret it
2) If they recall/ go out of lane; Hide near their minions and wait to go invisible.. Then jump them when they least expect it
3) if they have a favourite bush, make sure you hide in there and wait for them!

MAKE SURE TO WARD IN YOUR RIVER TO AVOID GANKS, YOU SHOULD BE FARMING AT A SAFE POINT SO YOU CAN EASILY ESCAPE

Post Mushrooms

Here your objective is similar. Except your have one more item to annoy with!

Utilising your mushrooms

There are three main uses for mushrooms;

1) Sight in the river - not only will this show you when a gank is going to happen. it will also deter them and the jungler will become fed up of getting slowed and poisoned
2) Bush patrol - placing your mushrooms in the bushes will stop them hiding in their and will give them no where to run! either when your jungler ganks or when your chasing them down
3) Place them in paths for you to run along... Now you should be playing a lot more aggressively! They have no Bush and no jungler to help! You should be pushing them up against their tower! and if they fight back, you have a handy trail of mushrooms to escape through!

Things not to use your mushrooms for;

1) Do not place them in minion paths.. this is a waste! by this time you will have your Runaan's and should wave clear easily!
2) Unless your losing your lane badly (which you definitely shouldn't) do not place mushrooms around your tower

Mid Game