Don't Play Him. That's what I want to say, but he distantly calls my name. I try to play him AP, On-Hit, AD, and Crit but i fail to succeed at all. Is it me? Is it him needing buffs or a rework? Halp.
UPDATE: I never expected actual advice, but I appreciate it so much! Tips on how to build, his cons, and current state help out a lot to me. Even though majority of you guys seem to think he's bad, I'll keep trying to play him! Don't worry, I won't in ranked C:
Watch DOPA Watch DOPA Watch DOPA Watch DOPA Watch DOPA
That guy has a 90% winrate on TF, and basically carries every game. If you want to win with tf, Watch DOPA.
If you like his On-Hit builds, check for his Klepto Rune set-up, and in terms of items he rushes Trinity Force followed by different On-Hit items based on the match-up. The idea is to proc Klepto as many times as possible and get your items fast.
As for AP TF, you have to realise that you give up lane power for Roaming potential. His Ult is very powerful when used correctly and it can be a huge game changer. When hitting 6, always try to look for opportunities to use it and help your team. Also try to coordinate with your jungler and support to control vision. TF can be very helpful with his Gold Card and if allies provide enough CC, he can chain CC opponents. He is also great at targeting isolated targets as long as he has vision control.
And one small trick, when you lock in Gold Card, the next time you Pick A Card, you will have another Gold Card as first pick (but it happens only once every time).
In terms of items, these 
are pretty much core, 
is always good in bad match-ups and always aim for a 40% CDR build to spam those Gold Cards. In terms of Runes, he is pretty flexible.
You should just experiment with him a bit to get a grasp of what play style suits you. He is very versatile, yet mechanically easy, focusing a lot on macro play and game knowledge to win the game. Based on which side of him you like, it may also change your play style as a whole
Skip playing him entirely. Everyone here will give constructive criticism but lets be real here: TF Is bottom tier trash with weak options. High risk low reward.
TF is in a bad spot right now because he's immobile, short ranged, has no sustain, and the only CC he has is unreliable. You have to give up lane to mostly everyone and if you don't roam and use your ult for ganking lanes, then it's useless to pick him. He doesn't really have anything to defend himself or stop people from getting on top of him.
Want my opinions? Grab a lichbane, ludens and maybe some stuff to make you tankyish like RoA, Rylai's Rabbadons and some boots. Find a squishy target, load up a gold card and Boop someone with it for a good 1/2 their health and finish them off with your Q and a few autos.
In my honest opinion your first item in lane should be a sheen.
