1. When a player is see-through and has wavy lines around them, run like hell
2. When you see a monster bigger than you and controls a large mob, run like hell
3. Beelzebub does not like to talk about the weather
4. Do not insult Baphomet's mother
5. Creamy does not like novices poking it
6. Creative shop names have a higher chance to make people click and buy (I usually use anime references now. The most recent shop I made is "SOS Brigade Maid Cafe Tsundere Ver.")
7. Right when you make good zeny selling a certain item, other users will start selling it to the point where the price drops so much you can't sell it at all, leaving a lot of those items in inventory that's not moving anywhere no matter how low you set the price
8. Those with VIP, are in guilds, and have money to spend in the Kafra shop always have an advantage against players who are dirt poor (myself included)