Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Stalker's vs Skirmisher's - It's personal preference really. If you feel like you need the extra CC for ganks go for a Stalker's. If you want to 1v1 assassinate people and do crazy damage take a Skirmisher's.
Boots - Boots of mobility are definitely the best boots on Talon. Helps you clear faster, catch enemies ganking and catch them out and assassinate them.
For your 6th item choice, you can choose between Dominik's, Death's Dance, Maw, Mercurial, and GA. If the enemy is staking armor (has people like rammus or malphite) then you should definitely get Dominik's Regards. If you're often getting bursted by the enemy AP carry then get a Maw. If the enemy team has a crazy amount of CC get a mercurial. If you just find yourself dying a lot get GA. You can get a Death's Dance when you're crazy fed and you don't need defensive items/the enemy team isn't stacking enough for a Dominik's.
Flash is an easy choice. Best summoner in the game. Gives him a reliable escape tool that he doesn't necessarily have and gives you a great initiation tool. Smite.... self explanatory.
Runes & Mastries
Marks - You do 100% physical damage so armor pen is very effective
Seals and Glyphs - average armor and mr no need for anything else
Quints - AD quints will greatly increase your damage
Mastries - Average thunderlords/ferocity tree. Thunderlords works really well on champions like Talon and is currently broken. You can take assassin in the cunning tree but you're relatively mana dependent so runic affinity works well.