A few tips:
Cities: Searching workshops, laboratories, and libraries can yield items, but may also result in penalties from NPCs.
Finding Wendy's oversized dildo in the workshop triggers a special event. Sleeping with Wendy has a chance of being eaten.
Searching Amanda's laboratory yields many unique items; basically, more than half of the game's quests require searching her.
The library is the only place to find special books and some strange items.
The school and swimming pool allow for undisturbed item searches, but be careful not to die from energy drink poisoning.
Marlie's shop currently only provides fixed equipment; sponsoring her doesn't yield extra rewards. Entering her shop near closing time will result in being eaten.
The police station allows you to complete quests or sell unwanted items. Remember to repair items before selling them for better prices.
The park is reserved space and currently has no use.
Islands: RESI offers free lodging, or you can buy a room at the inn.
Neighbor EZRA sells the gems you find on the beach.
The new character Holly can breastfeed to restore stamina… allowing players to mine more gems near Shark Village. (She cannot be X-rayed.) Given the incomplete gift system, it's not recommended to spend too much money buying items from her.
The inn has added reserved space, currently unused.
Otherworld: Talking to the maid reveals the new locations Queen's Garden and Magic Tower, and grants you your room.
Queen's Garden and the gate are reserved spaces and cannot be entered yet.
Each character can only escape from specific locations:
Amanda: Laboratory
AMY: At home (difficult)
Wendy: At home
Resi: After dinner
Serin: Beach
ROX: Gym (difficult)
Soraya: Library
Marilyn: While patrolling (difficult)
Marlie: While shopping
Diamante: Class (difficult)
Serin: Work (difficult)