General:
Before gang or poke or teamfight at early game you need to have 4 stack at your E(skill) to do more damage.

Its Time to Fight
use W(skill) to choose a card. BLUE: card deals more damage and you gain back 50 mana at first lvl so use this against minions or Jungle to get mana and deal damage. RED: card deals AoE damage to nearby enemys and slow, use this card for gangs or to clear tyour wave and more farm with your Q(skill). YELLOW: card deals damage and stuns target enemy for 1 sec, use this card to gang or invade.
After W(skill) use Q(skill) instant to deal AoE damage to your enemies or to clear your wave or to push your lane hard. W(skill)+Q(skill) (red card) combo well to clear and deals to damage to champions and enemies. W+Q (Yellow card) to gang.
About Gangs other lanes. First: Use W to choose card Yellow Or Red and then press R(skill) to teleport. Try to take good potitions. If you dont do that you may die.
About escape: When you fight or farming or roaming or whatever try to keep at least 250 mana at 6 lvl and ulty up to escape. Dont stay alone without vision or without mana, you are probably dead.

Pros
1 high burst damage
2 2 cc (stun+slow)
3 mobility
4 Very good farm cause of passive

Cons
1 Mana problems
2 Allies flame you cause u tale TF ad carry :P

ban whatever counters you cause TF is not so strong at early game, play safe against counters, be aggresive against champions who can kill, dont fear to teleport other lanes to take kills or assist. That makes you stronger soon. Take good potitions,Support your allies by buy pink wards . Wards are OP