Basic attacking combos

The first Ability to upgrade is Drain. This ensures that you don't lose too much health getting blue buff. I focus on upgrading Drain first, because it's the best thing Fiddle has, when also having a lot of Spell Vamp. When you meet an enemy, first using Terrify and then Drain is the best combo. You should now hope that he doesn't flee, because your Drain is continuing. If you haven't become underpowered of some sort, this should kill them. Should they try to get away, you can use Dark Wind, and hope it will bounce enough times. Dark Wind will still be very effective even though it isn't fully upgraded, as it also deals +45% Ability Power in damage. Don't try to run anyone down for too long, as the chances of you running into more trouble is way too big.

After getting Crowstorm

When you get your ultimate, using it from the bushes is very effective. If they've warded the bushes, you can still launch it from far away, and then use Flash to get close to them. Watch out not to use Flash before your ultimate has actually set in, because it will cancel your ultimate if used too soon. If you jump into a bunch of people, make sure to run along with them, as they will probably try to flee. Rembmber to use Dark Wind here. Spell Vamp will hopefully keep your health up. If you don't think your a double kill is an option, just Fear and Drain one person. 1 kill is better than no kill. Your ultimate should be able to give you a triple kill pretty often though.

Fleeing

If you are trying to get away from someone, and you think they've almost catched up on you, turn around and use Fear. If Fear is fully upgraded, this will give you a 3 second advantage. If more people are running after you, get your teammates over. If it's only 2 people, and you are more or less overpowered, you can try to Fear, Dark Wind and Drain, and hope Drain gives you enough health to kill them both. When Dark Wind bounces between only 2 enemies, it's very effective.

Attacking close to turrets

You shouldn't fear turrets so much late game. If 2-3 enemies stand close to a turret, and you have fully upgraded Drain, you can easlity ultimate into the bunch, if your friends assist you afterwards. Just make sure to use Dark Wind, Fear and then Drain, after your ultimate. Be cautious if there's a tank among them. You probably shouldn't do it if they're more or less fed - and you aren't.

Early tactics

1. Take out the Ancient Golem first. The newest patch (3.8) has increased the initial spawn time of Wolves from 1:40 to 1:55, so starting out at blue buff is more efficient now. Remember to use Smite here, as the cooldown time is roughly the same as how long it takes to move from blue to red buff.
2. You should be level 2 now, and with Dark Wind you'll be able to clear Wolves and then Wraiths fast. Remember only to use Drain on Giant Wolf and Wraith, in order to avoid mana shortage later on.
3. From Wraiths, you can either do a quick gank mid, moving through the bushes, or move on to take the Lizard Elder. Smite should be available for you to use again at this point.
4. After red buff, you move on to the Golems. These should get you to level 4, and you should now try to gank the closest lane. If no gank is possible, go back to Wraiths and then Wolves, in order to reach level 6 as soon as possible.
5. When your blue buff has expired and you eventually run out of mana, you might want to Recall and buy new items.

Other stuff

• Reobtain blue buff as soon as possible. The increase in mana regeneration is crucial for your ganking possibilities. When killing the Ancient Golem, make sure you have at least enough mana for using Drain twice.
• If at some point you have plenty of mana, Smite is available, and no gank is possible, move on to kill the Dragon by yourself - exclusively using Drain. Watch out for bottom laners.

With blue buff you shouldn't experience any trouble with mana regeneration. Although, as the duration of blue buff is only half as long as the Ancient Golems respawn time, you'll probably experience a mana shortage in these intervals. To fix this, Clarity could be an option, but Flash is way more important in my opinion. Therefore, I have added 9 Seals of Mana Regeneration. Many people tend to prefer Seals of Armor, and this is how we compensate for that:

1. 3/3 Hardiness
2. Getting Seeker's Armguard relatively early in the game

This should be enough armor against the average AD opponent.

I rely on Spell Vamp to ensure persistency throughout the game. Quintessences grant +6% Spell Vamp, and when added to the +20% from Spirit of the Spectral Wraith, it really does a difference. It comes in very handy when using Crowstorm, and it makes Drain even drainier. The remaining runes of Ability Power and Magic Penetration should be self-explanatory.

Offense Masteries especially provides an early game advantage, where Drain and Dark Wind will be very fearsome. I basically just upgraded every important Mastery in Offense, and then saw what I had left. Defense Masteries helps you in the early jungle, in case you should run into some sort of trouble. +30 health doesn't sound like much, but I assure you - it's far from insignificant.