What is the best way to prepare for a job interview where the questions will be mainly Behavioural?

These people interview people like you for a living. They know what to look for when talking to interviewees.

My best advice is to answer each question honestly. Don't hesitate with a response, unless it really requires considerable thought before choosing between two options. Like which would be safest and which would be most profitable.

Don't bother lying. They won't be fooled.

Just say you don't kill people and able to work without shitting yourself.

Don't take yo medication