Hi guys, this is my first build for League. I think I have quite a good knowledge of Talon and can play him well. I hope my guide helps people, it's what it's for. This build will not guarantee success so if it doesn't work for you once, try it again.

Pros

Great farmer with Rake
Durable
Good Harass
Great Escape
Brilliant against mages amd ability reliant champs because of his targeted silence blink

Cons

Easily countered with armour as he deals no magic damage
I honestly can not think of any more, he is a very very good champion

I take 21/9/0 masteries, I find these to give Talon very good damage and they provide him with a bit of defence to keep him alive early game and help pick up that first blood. The innate life steal along with your Doran's Blade gives you a very heavy advantage over the opponents early game. This along with Veteran's Scars and Durability equals a very tanky hard to kill Talon.

The Good

&
These are my choices, but other viable spells are.
A good alternative to Flash
Great for finishing off kills, and could replace Exhaust.
A reasonable replacement for Exhaust.
Good for those heavy CC teams, this along with your ulti means an almost guaranteed escape, should replace Exhaust if used.
Reasonably good, nice for making enemies over confident in killing you. as you can heal bait, should replace Exhaust if you want to use it.

The Bad

NO!
Pretty much useless, this is unneeded as attack speed is not a required stat and Ability power is completely unused by Talon.
Are you jungling? I thought not.
Just bad in most cases, falls off massively late game and has quite a high cooldown for what it does
You are not a pusher, or a tank, this is unneeded.
You're no support

MercyMercy
Talon's autoattacks deal 10% additional damage to any target that is slowed, stunned, immobilized or suppressed.
This is a very very good passive, it makes items such as Frozen Mallet a must on him. With this you need to prioritise the cced target in a team fight, as this means they die faster.
Noxian Diplomacy
Talon's next autoattack deals additional physical damage. If the target is a champion, they will bleed for 6 seconds and be revealed for the duration.
A very good ability that makes autoattacking look old and pointless. The bleed is very good for finishing of kills and chasing, as it reveals.
Rake
Talon sends out a volley of daggers in a cone that then quickly return back to him, enemies are also slowed for 2 seconds.
This is very useful for farming and it also does quite a lot of damage. This is also used to proc your passive before you have your frozen mallet, it also helps you catch up if cutthroat is on cooldown
CutthroatCutthroat
Talon instantly appears behind his target, silencing them for 1 second and amplifying his damage against that target for 3 seconds. This is your chasing, your anti-mage, your escape and your single target steroid ability. This ability has so many uses, from jumping to a minion to dodge that Javelin Toss to silencing that Karthus mid Requiem channel.
Shadow Assault
Talon disperses a ring of blades outwards and gains stealth for up to 2.5 seconds while gaining 40% movement speed. When Talon emerges from stealth, the blades converge on his location.
This is Talon's bread and butter ability, this has so many uses. If you're being ganked by that fed Tryndamere from bottom, this can help escape, if your going one on one, this can provide that much needed damage to finish the target quickly and cleanly and with the cooldown reduction in this guide, it's available every 30 seconds at rank 3.

I start off with a Doran's Blade This gives good early game damage, a nice hp boost and a bit of lifesteal to finish it all off. Good for early game sustain.
I next buy Boots and 2 Health Potions
Then you may ask, "But what boots do I get?" Ionian Boots of Lucidity of course, the cooldown reduction is very nice for an assassin, but Berserker's Greaves are also viable, but if you want to be able to troll and put out tons of damage with your ulti every half a minute then pick the cooldown boots.
My next item is The Brutalizer this provides some nice cheap damage, armour pen and Cool down reduction, which as we all know is important on assassins, which I build into Youmuu's Ghostblade later on.
Fourth I buy Frozen Mallet this is in my opinion one of the best items for Talon, the passive slow interacts amazingly with his passive.
Bloodthirster is next, giving another great boost to damage and also brilliant life steal.
Sheen gives a nice damage boost to Noxian Diplomacy and builds into Trinity Force later.
Then Trinity Force and Youmuu's Ghostblade.
And finally you'll want to pick up either an Infinity Edge or and Atma's Impaler
The choice depends on if you would like pure damage or a bit of damage and some armour.