Overall, I haven't played much Talon Top and I don't know my matchups. So, this may not work out for everyone. Also, I'm silver 3 ;)
Basically, I was a Talon Mid main to a JG main with Kha'zix and into me today, a Talon Top Main.
KEEP IN NOTE:
This is only based off of my opinion and experience high elo players.

For your First Back:
Most of the time you will back with around 1100 gold. So, buy a control ward with your Serrated Dirk. But if you can buy boots buy it instead of the control ward.

Core Build:
Always rush Duskblade first and buy Mobis if you want roam. Ninjas if you need the extra defense. And go Mercs when they have a lot of cc.
VS Tanks
Tanks will build Armor eventually. So prepare for it.
VS Squishies
Go 1-SHOT
Situational Items
Go complete your Armor Pen item on like your 5th or last item. I've found that Youmuu's isn't as good to rush compared to Black Cleaver. And Maw VS Fed AP or AP heavy teams.
Offensive Items
Just get some dmg in. Only go I.E if you're sure you can get your q crit.
Defensive Items
You only need like 1 real tank item. And Scimitar and Maw don't count. I've never used Sterak's but, it should be good.
My Final Build
These are in order. Sometimes you can switch Youmuu's for like Maw. Or Mortal for your Scimitar.