cut this short
playing fiddlesticks for 15 games and changed build every game
and best one I got is...

movement speed

yes movement speed for fiddlesticks great for throwing silence, terrify and chasing them when running away from crowstorm

my first guide by the way
so reading this may suck
but doing it would be awesome

1st
runner mastery
help in a lot of ways

2nd
just changed ghost to clairvoyance
good for supporting

3rd
fiddle is squichy
but with this it should help a lot and you'll get a 4% ap bonus

1st build
you would get 387 movespeed at lvl 1 harassing anyone in the lane with dark wind without a single problem
mark the usual
seal average mana regen and health
glyph cdr and a little magic resist
quintessence ms

2nd build
mark runes ar basically for farming
kinda other same as above

3rd build
this was my build before doing the MS
ap for better drain
seals are HP
and glyph as almost 7% cdr

Flash is needed
to correct your miss crowstorm or just to extend the range (do not use flash while casting crowstorm, it will be canceled and wasted)

Clarity
when i roam

Clairvoyance
to see beyond

Ghost
to run faster then anybody ( i can outrun a udyr with just phantom dancer )

Exhaust
could be useful

Cleanse
to remove than exhaust when you drain / crowstorm ( not sure if it still does)

Teleport
Responds and save a team from a clash

others
i don't know...

pros

most people will think he's squichy but not with this build
cannot be chased alone or even by a team (depends)
people usually run if you cast drain on them (that's what the level one drain is for)

cons
after a few ganks people will tend to know your drain sucks and will start to go after you
you will still think it's squichy but it's really not
mana is kinda low when you spam too much
drain will not help much (build 1 and 2)
quicksilver stash will be your worst nightmare

this
is
very
important

but i can't explain it good
fiddle is very good disabler but people tend to use him as a AP killer

targeted silence and disable is scary... very very scary hit these right and you'll change everything

you will need to start sticking with your team mates when you can't kill anyone with crowstorm anymore (thats around lvl 10-13)

you will be initializing the clash as often as possible if not stay back and throw dark wind till you can terrify someone off the enemy team and start a clash (unless they leave him that is)

he's a picture of my match history (last 10 games)




3rd pic
im not sure how you'll judge this but this is one game after this whole guide

and i only have 50 ap here (moonflair spellblade)
shaco was pretty much targeting me most of the time (didn't have a chance to get oracle) and i was chasing everyone with silence then close in fear and let my team handle the rest, if a clash occurs i just stay back till cd finishes or just look for their fiddle and start canceling his crowstorm then i'll cast mine, also our mundo took oracle around late game so shaco was a breeze :)