I've chosen to make a fiddlesticks guide because, i don����¯�¿�½������¢������¯������¿������½������¯������¿������½t find any of the guides in here useable. What makes fiddlesticks one of the greatest champions in the game (if played right) Is the fear-drain combination.
I have the best experience playing fiddle as jungler. Lane is of course an option as fiddle but I would suggest another build then.

Runes you can choose what you feel for, but i like AP, MP and Health.
Fiddle needs a hell lot of AP and therefor i found AP and MP as a need. Health otherwise could be replaced by something you like better, but it is what i prefer, as fiddle is a weak champion and will be in need of it late game.

For jungling you will need Heal, or Smite. I prefer Heal, though it will be a slower jungling. But! The issue by taking Smite, reveals for the enemy that you will be jungling and they will probably gank you.
The second and the most usefull mastery for fiddle is: Flash
The reason why heal is very important is that it will make your crowstorm more effective. As soon as your crowstorm has been casted, you flash to get as close to your openents as possible.

The list speaks for itself. I've recently started to use the will of ancients, because it makes your drain life heal you for an additional 20% and makes your crowstorm heal you greatly, so you in the late game will become almost invincible.

Zonya's hourglass is an option and only necessary if you need the additional armor in the late game.
if not necessary and the enemy team has bought a lot of magic resist, then get void staff.

You will go for reaching 5 lvl's in drain-lifeasap, because it is the reason you won't be able to go down. Fear comes afterwards as it makes you less likely to be interupted in your draining. You should get a single spec in dark wind because of the silence and it is very good for taking down fleeing champions.

The first thing you have to do, is getting mana buff. You will need to use both your heal ability and you healing pot. After you go for wolves, and then the 4 "vampire looking" creeps.
If you have specced your masteries as i've recommended, you should be lvl 3 now and able to take out the lizard with drain life lvl 2. If not skip him and go for golems and return to him after when you have reached lvl 3. Next you head over to the enemy field and go for their mana buff, wolves, and jungle untill you reach lvl 6. Now it's time to gank!
Remember, be sure to have mana buff on you all the time.
if fiddle is out of mana he is as good as dead.

Fiddle is in my opinion, the best champion 1v1.
His deadly drain and fear combination, makes im invurnable against almost every champion.
If you are being chased by another champion with full hp and yourself only has around 50% dont be afraid, cause this will be the death of your enemy.

Run into a bush and let him follow you.

When they get to the bush and you have been revealed, fear him and drain asap!

Now you should have around full hp and he is the one who is down to 50%. silence him, and keep draining and the victory will be yours!
if the situation is: you versus 2 enemies, you crowstorm towards them from the bush, fear the one of them (the one with the highest dps) and drain him. This will grant you 1 kill for sure and the other champion will probably flee from you.