You just need to mix it up a little with weed, alcohol, MDMA, maybe a psychedelic and/or a little ketamine. Try not to mix substances together though.
One idea:
Day one: cannabis, ketamine
Day two: psychedelic during day, MDMA on night
Day three: cannabis, alcohol
Or
Day one: cannabis, psychedelic
Day two: MDMA, ketamine
Day three: alcohol, cannabis
Endless possibilities, you get the idea though
Maybe a little speed can be good just for keeping you up and dancing on one or two nights
But like I said don't mix anything unless it's just weed + something (and you're comfortable with that combo already) or maybe ketamine coming down from MDMA. And don't ingest too large doses of anything.. Light to moderate doses will be fine in such an overwhelming environment.
I'd stay away from most other drugs, these are the safest and most conducive to a festival atmosphere IMO, and the least likely to make you do stupid shit (except alcohol). and don't buy drugs on-site either
Edit: oh and nitrous, as needed
how could I forget that