Hello Everyone!
I love talon mid and play him all the time. Im not pro but this is how I play talon
I will say what and why i build things. I will Most likely update this build wiht more information. But this is my first build so it will be small.

Sorry this is my first build and I dont know how to use pictures and stuff.

At the end of your build you should have Mercury's Treeds, Yoummuu's Ghostblade, Blood Thirster, Infinity Edge, Trinity Force,.

Why?
Mercury's Treeds give you magic resists and mid lane is mostly ap.
Also many mids have lots of slows and stuns such as Veigar and the Tenacity will help.
Ninja Tabi is optional if there is an ad mid.

Yoummuu's Ghostblade gives you early game armor pen and its passive goes very well with your ult. If you need more pen you can always switch to the item last whisper. This can be a good idea if people are getting thornmails.

Blood Thirster gives you sustain in lane and gives a is the item that gives you the largest amount ad.

Infinity Edge gives a large amount of ad and crit make you q do a hell load of damage. So the passive is great with your q.

Trinity Force is great for talon because the extra damage and movement speed helps alot.
The awesome part is when you basic attack you slow your opponent. The passive which makes your attack 2.5x stronger after you use an ability. Goes great wiht you q.

Ignite- Works great for diving with talon. Your q is like a mini ignite so both of them together with your silence makes a great combo to dive.

Exhaust- Helps if ad mid and when mid players carry flash this is a great way to catch up.
I get exhaust because you never know when you are going to have a ad mid if you play blind pick.

Pros

- Great early/mid game
- Insane burst damage
- Counter mid
- Overpowered
- Great 1v1

Cons

- Bad against tanks
- Falls out a bit late game
- Hard to farm with

With mid lane talon i think it is hard to farm without any mana regen or life steal early game.
I rely on kills so ignore being talon mid if you play passive. Best way to farm is to harass so you can farm without them poking at you.

This is my first guide. Its not really a guide but i hope it helps. Please comment and give me tips on my guide and how to make them better. Again this is my first guide and would love to learn more. Please Leave some sort of message