Go to the Genocide Museum. It’s somber but they did a very good job storytelling. Get the audio guide for the extra $3, it’s pointless without it.
Visit the marketplaces. There are various ones around town with Central Market being the crowned jewel.
There are many expats living in Phnom Penh due to its affordability as well as it’s culture. Talk to them. You’ll learn so much from them.
Get a massage! It’s cheap like Thailand and all the massages I got were fantastic and far less transactional. I had many memorable conversations with some very down nice masseuses. Perfect place to practice bridging the communiction chasm in a fun way. Lots of laughs and honing your charades skills.
Go to the Olympic Stadium just before work let’s off. Watch the athletes working out, students arrive in cliches, and working class show up. It’s where everyone goes to hang out plus it’s a magnificent place to catch a sunset.
At no point did I feel at risk but there are signs and the locals tell you to be careful with phones and bags which apparently get stolen by people on motorbikes.
Go to Romdeng if you are an fearless eater. Try the tarantula if you dare!
It can be a bit boring there if you’re unwilling to explore and mix it up with the locals.
Fresh juice is hard to come by in Cambodia. They prefer to mix juice with milk for a creamier sweeter sugary palette. It’s not as thirst quenching as just plain squeezed juice. Odd decision since it’s always baking hot.