imo advanced techs include:
-ASC sheild cancelling (possibly into grabs)
-foxtrot/pivot/turnaround smashing
I use this to run behind opponents and execute fsmash or dsmash, usually they realize im behind them by the time they are getting hit.
-Side B full dash cancels (into VSJ, grabs, or an executed side b> aerial/stool/up-b)
This is probobly my new favorite approach, it seems to be one of the most reliable.
-long distance HA executions, or HA recoveries that go firther than sonic's up-b would (which is possible)
-using up-b to go through an incoming aerial, your apponent bounces ino the air for punsih
-hitting some one with sonic's face during a bair. (this can be a very unexpected strike, and it can also be used to make sonics bair knock people in the direction that sonic is facing, so you in essense dont need to RAR if you master this)