For public settings, stick to less than 0.5 grams. Remember to take deep, steady breaths and keep in mind it's just a trip (Such is life).
If you're taking higher doses, do it alone (or with an experienced user) in a calm environment and prepare yourself mentally and physically (mindset and setting are crucial) because you'll experience various states of being (the merging of higher and lower selves might be unsettling initially).
Ultimately, it's a spiritual journey that demands utmost respect.