To Tutoyer or Vouvoyer? Always a dilemma for me

After 9 years in France, I still get a big headache each time I speak to french people I just know. I never know if we tutoyer or vouvoyer that person. Tutoyer is the informal way of addressing 'you' while vouvoyer is the formal way. In english, we get away with this as everyone is 'you'. In chinese, it is easy as all seniors are '您' out of respect and others are just '你'.

In French, for people whom we do not know but we deal business with in our everyday life like the butcher, the baker, waiters, cashiers etc... we use 'Vous'.
For older people, we usually use 'Vous' even if that person uses 'Tu' at us. We can tutoyer the person if he/she invites us to use 'Tu'. Same goes for boss at the workplace and sometimes even colleagues, teachers in school and neighbours etc.

My problem is that I can't distinct some grey lines.
I vouvoyer my in-laws. So naturally I vouvoyer their friends though some told me that I could tutoyer with them. Yet, each time, I could not decide on which to use. Sometimes, I could start with 'Vous' and then continue with 'Tu'.

Neighbours is another grey area. I have been vouvoyer all my neighbours. And I never paid attention if they vouvoyer or tutoyer with me. I realised it was becase each time a french spoke, I translated in my head from french to english. So when someone said 'Tu vas bien?', I would naturally processed in my head as 'How are you?'. I would answer 'Oui, je vais bien. Et ....' That was when I got stuck. My reply was 'Yes, I'm good. And ....' But which YOU to use in french? I had not listened carefully earlier if that person asked in 'Vous' or 'Tu'. So to be on the safe side, I would end with 'Et vous?'. I did not want to upset someone if that person 'Vouvoyer' me and I 'Tutoyer' back. Now, that person might think I was being a snob by using Vous. She might continue to use 'Tu' if she understood that I am a foreigner or she might revert to 'Vous'.

Recently, we invited our neighbours opposite for an apéritif (a pre-dinner drink). We had a good 2 hours chatting and getting to know each other. They have 2 young boys like us. After they left, I asked Seb 'Did you vouvoyer or tutoyer with them?' Seb replied 'I tutoie as they are our neighbours.' I was like 'Ah bon. I have been using vous throughout the whole time.' Gosh.

I decided to open big my ears now. So far so good. Once I was going to my gym class in the village multi-purpose hall, I met up with a fellow gym mate on the way. We exchanged bonjour and she asked 'Tu habites où?' I paused for 3 seconds before telling her which street I stayed cos I was processing on the 'tu'. She must think that after living here for a few months, I still could not recall my street name.

Another strategy I used was to wait for the person to start a conversation and zoned in on the 'tu' or 'vous' used. These could cause awkward situations as each of us was waiting for the other to start talking. At the school gate each morning and evening, I would say the usual 'Bonjour' to the other mothers. Sometimes, I waited until a mother asked 'How are you?' before replying and asking back in the same way. Most mothers use 'tu' at me which was a relieve for me. Now I have to note who to use 'tu' on and who to use 'vous'. I would certainly need a little black book for that.

On top of that, I would need to note down who gives bise (kiss on the cheek). That itself calls for another post.

This is a long post but as I told Seb, I could write a book just on this. I doubt I can ever adapt this usage of tutoyer and vouvoyer as natually as the french do.