I had my SGU skype interview in late Feb. I think I was horrible (I couldn't answer the basic interview question" talk about a time when you took a leadership role) but I still got in somehow..
What tips I would give is:
1. Dress well.
2. Be ready to talk about "talk about a time" kind of questions. For example: when you took a leadership role, when you had a major conflict with a peer/someone else and how you solved it, overcame a challenge, dealt with a failure (academic, probably another), etc
3. The obvious question: Why medicine?
4. Three qualities essential to become a physician?
5. A current healthcare issue (any)
6. 3 steps you've taken to reach here where you are? (for example, did a post-bacc to improve your GPA, etc)
7. What kind of doctor do you want to be, i.e. what specialty and why? (I think they are basically making sure you're realistic about your prospects (so no 'dermatology or bust') and you have appropriate reasons for the choice (i.e. don't say 'it pays well'))
8. How do you cope with stress.
9. How will you adjust to Grenada, have you thought about it, etc.
And so on... it is also a good opportunity to find out more about SGU, Grenada, etc. It's nothing too stressful; like I said - I thought I was bad, skype interviews are just different, but it was all good.
The interview pretty conversational. We talk quite a bit about my background, etc (I wasn't explicitly asked where I went for undergrad, but I still mentioned and talked about it where it was relevant)
PS the skype interviewer knew NOTHING about me, not my major, not my undergrad uni, not my scores, not my personal statement, nothing. All they knew was that I was applying to the 4 year med program.
Update: they DO NOT ask you to write an essay anymore during the interview. I was never asked to write one and I was told by the interviewer "SGU removed the essay writing component last year from the interview process"
Good luck!