Ok, lets see. What do I do with a goon.
VS S1: Pretty obvious. Pounce the nakes = insta kill, headshot = insta kill. If there is a shotty that is crouching, pounce chomp. Or if you are already near, it is harder for a crouching shotty to aim (and dodge of course) so a lot of people will circle chomp. Just like a simple wasd circle dodge, only chomp when the circle gets you in range.
VS S2: Pounce, Chomp Chomp is pretty effective. Sometimes the pounce fails and you just have to finish with 3 chomps. Which is fine since the pounce got you close enough. I would recommend (if you didnt already) going on a devmapped server and doing /cg_drawbbox 1 so you can see the humans bbox. You really dont have to chomp near the head, just somewhere on top of the bbox.
VS S3: Chainsuits are my very favorite thing to kill as goons. I have a pretty simple yet fairly effective tactic against the average chainsuit. Pounce Pounce Chomp Chomp. Im sure others have done this before too. Generally a lot of people just try to get 4 chomps. THe problem with that is, (for me anyway) that the chaingun rips me up too fast. So I pounce twice to both do damage, and dodge fire. Then its 2 headchomps and hes dead. The only flaw is that if the bsuit is ready for you, his medi can quickly add an extra chomp. So if this is the case you may want 3 pounces and 2 chomps. Either way I think thats better than just goin for 4 straight chomps.
Lucis are a whole different story. To be honest I never really did figure out a great way to kill a luci. Bsuit luci I try to use my chainsuit method, doesnt always work because pouncing straight at a bsuit is an easy way to take a luci to the face. So some times I just go back and forth chomping away at the head.
Battpack lucis..I treat like s2s but I usually fail at killing a good luci.
Other notes for goons.
Double Pounce: AKA Corner Pounce
Pounce, and once you release mouse2, hold space. Very effective for escaping. Also effective at killing rets:

Double pounce on the ret and fly safely away, then double back. Only takes 2 to kill each ret.
There are sooo many cool goon tactics, that I really cant post in 1 post, very hard to explain so I can really only demonstrate.