I would think about the process of problem-solving. Be prepared to talk about how you would go about solving a problem or deciding on an action.
For example: What would your priorities be in an emergency situation? (Circulation? Airway? Breathing? Calling for help? etc.)
What would do if you had an unfamiliar clinical situation? (Look something up in a resource manual, policy manual, etc.? Ask a colleague for advice? Make sure the patient is safe before you did anything else? etc.?)
How do you go about making routine decisions about common patient care situations? (Assess first? Diagnose? Plan? Intervene? Evaluate the effectiveness of your actions? etc.?)
How do you deal with interpersonal relationships with your co-workers, patient families, managers, etc. (Do you have any general principles that you tend to follow -- such as not gossiping ... or handling a potential problem by talking with the individual directly and early before the problem grows into a big problem ... etc.)
In other words: In many cases, the key part of the answer to a scenario question is your revealing how you would go about deciding on your actions. Do you panic? Do you throw proper procedure out the window? Do you use your resources appropriately? etc. You can't prepare for the actual scenarios as you don't know what they will be. But you CAN prepare to discuss you approaches you would use in any scenario. Have those common approaches (and words) in your head so that you can demostrate that you would use an appropriate approach to keep the patient safe and deliver the appropriate care -- even if you had to look something up or ask for some help in the process.