Talon's main combo's are:

2nd level cheese:If you don't know about 2nd level cheese: if you use a rake, q the
aa+ignite to kill most squishies]
Melee Combo: If you are rooted or they caught up to you, melee q,w+aa to proc passive
Basic combo: It's actually kinda complicated, but easy after a bit of practise, W,
before that hits, ranged Q, and before That hits, throw your ult in mid
air then aa to proc passive.
Teamfight Combo, Go through the jungle to get behind the enemy front line, then e over
a wall and hit as many people as you can with your w and ult, (DON'T
Q!) AA all of them, proparly done, you should have a w, a ult and a
bleed on everyone
https://www.facebook.com/leagueofchallengersph/videos/nine-combos-every-talon-should-know-talon-combo-guidecredits-staxl-httpsyoutube7/1668692716505806/

You can't actually help your jungler with the red or blue buffs, you're gonna need the CS. Try to get a gank early, everything now is about getting a lead. After that, wait for the perfect opportunity, and use your massive burst to obliterate your opponent. If you see your jungler in a fight with the enemy jungler, go and help. You have amazing roaming ability. Abuse this.

Try to grab rift herald at the start of this phase. wait for the perfect opportunity to use it. If you use your combos right, you will be fine, but try not to die.

If you haven't ended the game yet, you start to fall off here. try to 1v1 and not team fight.

The fact that you are a heavy burst assassin allows you to bend some of the rules noobs are taught. If an enemy has more health than you and your low, make some calculations. Quickly ask yourself: Do I have enough mana? Will I be able to kill them? Do they have any CC? If they have CC is it on CD? If all these are a yes, go quickly, kill them, get out.