to poke his combos are QE (either in hammer or cannon form). His combo to go in is QERQE. (shoot, run through gate, hammer form q then run behind him and smack him towards where you ran from) --- GT: DeLaMal LoL: Cascayde
Items vary, but pretty much everyone does the same thing nowadays, with BT, brutalizer, last whisper and a tear into manamune.
Skills can also vary from maxing Q first or not getting points into his ult until Q and E are maxed, it's personal preference really.
An example is: QEQEQEQEQE or QEQWQRQEQ
Lastly Talon is an assassin with a weak earlygame so try not to die when he gets to level 6, other then that just poke him to death or kill him after he attacks you, results will vary. --- Kitty Kat --> /\_/\ .................=(^_^)=
"When teamfights begin, I am both Mundo and Ezreal"
4. Trinity Force
"I suck at Jayce, unless I am in jungle"
"We have Nidalee and Caitilyn in our team"
Those are my most common ones. My favorite item on Jayce is Ghostblade since you can do trick to trigger it in melee form and switch to ranged to have full buff duration. Also I like to abuse crit chance out of random items like Ghostblade+Atmas. I build this combo a lot, sometimes mixed inbetween Sunfire, sometimes Banshees Veil (actually combo Ghostblade+Veil+Atmas is very strong and cheap and gives everything and I get IE as followup item most of the time.
SotD is second best item for Jayce and makes him assassin. I build it as my only AS item when I play ADC Jayce (and I play that quite a bit). Along with W gives him such an incredible burst.