The process is all competencies-based in my department , we're not allowed to ask anything that doesn't relate to a competency or skill listed in the person spec.
Person spec should list the relevant CS behaviours at the bottom, so you can look them up and get a good idea of what they are looking for. Have them in your mind when you answer - so, if they want someone who can operate effectively in a busy business environment then read up on 'working at pace' and have a couple of examples ready of what you did and how, how this shows your skills and competencies, and how this benefitted the organisation etc.
Favourite 'standard' question at our place is "tell me about a time something went wrong/you missed a deadline /a stakeholder was unwilling to cooperate " or similar. Maybe have an example of this, of course with an explanation of how you turned it around and improved processes to prevent it happening again.
In my organisation interview questions are scored numerically. So if I ask you a question about your project management experience I need a relevant example that touches on your skills and relevant competencies, if i am to give you a high score. Interviewees are ranked according to overall score at the end, so even if I really like you, if you've given wishy washy answers and not answered the actual question, you're probably not going to get a high score. Always worth checking "is there anything else you'd like to know?" if you're not sure you've nailed the question - gives the interviewer chance to rephrase if you've misunderstood or to ask a follow up question for more clarification etc.
Any experience they ask for that you don't have, just fess up but enthuse about the opportunity to learn (after all it can't be an "Essential" skill if you have been invited for interview). Last interviews I did, 5 people looked me in the eye and assured me they knew how to analyse data but when I then presented them with a simple 1 page analysis and asked them to comment on what they would conclude from it, only one could actually put a sentence together. The job ended up going to someone who said right away they only had limited experience in that area but would love to learn. And 6 months in, they're doing very well.
In the event you are unsuccessful, ask for feedback. Don't know if this is the same across the board, but we are required to share our scoring sheets and comments with unsuccessful candidates on request, and it may help for the future.
Of course, I hope you're successful and wish you all the best!