This is my first build, and I always play characters differently than others, so feel free to change masteries or anything you feel will work better.

Intro:

Fiddle Is Always Used As An Ap Character, But I Like To Twist Things Up And Use Him As A Tank, It Seems More Effective To Me. Besides, It Is Always Fun To Try Something New ;)
I Almost Always Take Ghost Because It Is a very effective summoner spell when it comes to escape (since flash is going to be removed, I find it more strategic to not use it to reduce reliance).

The Second Summoner Spell Doesnt Really Mater; Exhaust Is Always Usefull, but Cleanse is an option, as well as ignite which can topple on your Drain for extra damage.

After Rod Of Ages, The Game Is Pretty Much Over. So What Ever Will Help Your Team Will Work. But If You're Getting Beat Up By The Other Team, Like A Tryndamere Or Xin Zhao, Get Thornmail Or Something To That Sort. If You're Getting Alot Of Kills, Or Assists, Mejais Is A Great Idea Also.

Solo Is Very Good. Fiddle Is Very Capable Of Being A Solo Lane, I Have Done It Many Times And It Working Out Most Of The Time. If You Go Ahead And Be Tank Fiddle, Some Games You Will Die A Lot But For The Teams Sake, Sometimes You Will Get A Lot Of Kills/assists.

Beginning Of The Game Is The Most Important, Lane With Someone Who Can Either Stun Or Dish Out Early Damage. Regrowth Pendant And Drain Will Help You So That You Most Likely Will Not Die.

Once You Get Warmogs, It Is Pretty Easy Going From There. You Can One vs One Against Anyone, Even Tryndamere With His Ultimate (unless he buys Madreds)

Items:

Warmogs Is Great For The Health And Health Regen, So I Always Start Out With It On Him.
+920 Health +30 Health Regen Per 5 Sec Passive: Permanently Gain 4.5 Health And .15 Health Regen Per 5 Sec Per Minion Kill. Champion Kills And Assists Grant 45 Health And 1.5 Health Regen Per 5 Sec. Bonuses Cap At +450 Health, And +15 Health Regen Per 5

Boots Of Swiftness: It Is Great For You To Catch Up To Enemies And Terrify Them, Making It Easier For Your Allies To Catch Up And Kill Them. Also Helps With Get-aways, And When You Use Your Ultimate.
Unique Passive: Enhanced Movement 3

Rod Of Ages: Also A Great Choice For Fiddle, Giving Both Health And Ab.
+450 Health +525 Mana +60 Ability Power Passive: Your Champion Gains 18 Health, 20 Mana, And 2 Ability Power Every 1 Min. Bonuses Cap At +180 Health, +200 Mana, And +20 Ability Power.

Rylais Scepter:
+500 Health +80 Ability Power Unique Passive: Dealing Spell Damage Slows The Target's Movement Speed By 35% For 1.5 Seconds (15% For Multi-target And Damage-over-time Spells).

Abyssal Scepter: Great To Help Your Team And Also For You.
+70 Ability Power +57 Magic Resistance Unique Aura: Reduces The Magic Resist Of Nearby Enemy Champions By 20.

Guardian Angel: Good If You're Having Trouble With Staying Alive, Feel Free To Get It Sooner If Needed.
+68 Armor +38 Magic Resistance Unique Passive: Revives Your Champion Upon Death, Restoring 750 Health And 375 Mana, This Effect Can Only Occur Once Every 5 Minutes.

Also Banshees Veil Is A Great Item If You're Having Trouble Getting Your Ultimate Off, Or Just In General.

Strategy:
Fiddle Can 2v1 If He Is Soloing Top Or Bottom Lanes Very Easily.
Since Fiddle is labeled as fragile, and since that is his worst attribute, amping that up along with Rod of Ages really sets up a good early and middle game (late game might be kind of weak, but the game should be over beforehand).

Situational:
If The Team Is Heavy Attack Damage, Change Rod Of Ages For Sunfire Cape.
Or If The Team Is Heavy Magic Damage, Switch Rod Of Ages For Banshees.

Please:
Try The Build First, Before Voting.
Comment.
Tell Me If I Did Anything Wrong, I Am Sure I Did. Criticism Is What I Want! But If You Don't Like It, Leave It Be, Don't Hate :)