This is the way I normally play twisted fate, as ap tf does the most damage early. By this I mean that AD does a lot more late game. AP TF mid is very good, but play him passively unless you are very good at Pick A Card.

To harass your opponent as TF, what you do is you use your Blue Card. Reason is, it is your biggest damage dealer and you waste no mana (while gaining some), people may think to use others, but using your other cards is only when they either dive you, or you are getting a gank from your jungler.

To farm (a bit later game after you fully build your Morello's), you can farm alot easier. To do this, wait until the entire wave in bunched up, then red card the caster minions. After that, wild card all the minions at the side close up. This will either kill (if you have enough ap), or have them at extremely low hp.

The reason you don't start with a Doran's is because you do not need the low mana regen, you can just Blue Card and the Amplifying Tome gives more AP. The reason for the mana regen items in the build after what I had just said, is so you can use your abilities faster when fighting an opponent.

ADC TF is played often, but doesn't get as much as he should. The reason being is that he is the only ADC that can gain mana from an attack (Sivir can gain mana from opponent abilities so this is different), and he is the only adc with a Stun as a normal ability and not ultimate (Caitlyn also but her's is a trap and can be easily moved around). He also has a slow like many other adc's.

What is nice about ADC tf also is that he gains the extra damage stack from his E (stacked deck). Also with his E, he gets cooldown reduction and attack speed. This is why you max it 2nd. The reason you max your Pick A Card first is that it is his only real damage dealing spell. His Wild Cards should only be used as a kill secure when they are too far away.

As I had said in the AP TF guide, using your Blue Card is good for harass, but for AD, I think that using your stun/slow is better for AD TF because he can do a lot more damage if the enemy is stunned.

If you choose ADC TF, good supports to have are Sona, Taric, or Alistar, the most played supports anyways. The reasons is that they give attack and ability power buffs which are great because early game, ADC Tf isn't much of a damage dealer. The reason Alistar is in there is because Alistar can knock them back, into stun range for TF to stun them. After that Alistar can knock them up. And by the time all that happens, TF can have another Stun/Slow card.