You need to get Siri to know who your contacts are.
I did the following and it worked 100% and remembered details about my office, my brother, sister etc.. etc..
Ask Siri: Who is my wife?
Siri will then ask you to tell her who your wife is, she will then pull up the details from your contact and you simply need to confirm this.
Do the same for all other contacts you want Siri to remember.
As for locations, all you need to do is open your MAP app, type in an address and then place a pin there. Click on the PIN and then ADD TO CONTACT. Once in the contact simply add the tag, i.e. Home, Cinema, Office etc..
Siri will now remember this when you ask: Remind me to check the water when i get home.
Since it will know what your home address is it will create the reminder message.
When you ask it to: Send a text to my wife and let her know that i will be 30 mins late. Siri will auto create a SMS message and write: I will be 30 mins late!
Hope this helps,
Regards,
Jay