TF has the most reliable stun in the game paired with rapid fire cannon. Not only that but jungle TF is like a mid TF that is constantly roaming. This creates immense pressure on the map when ahead. Approved by bot lane and that's enough for viability for all games at all ranks.
Protip: Don't listen to those meta slaves.

First you need to learn how to kite camps

ALWAYS start krugs (smite)

Second camp is raptors

Third camp is Red (smite)

I recommend ganking after hitting lvl 3 at red

Try to gank as much as possible, farming jungle is a second priority.

Playing TF jungle = more invades, be careful! ward the brush occasionally

Stun cards are your best friends for engaging, escaping, kiting, etc.

Engage with gold card and put some AAs into CC'd enemies.

Spam your Ghost to escape, engage, and reposition.

Rapid fire cannon will make you more efficient at engaging with the extended AA range.

This is a game so play it for fun, but win it at the same time. Jungle TF allows both of these to happen.