If you have earned you certificate, you have the knowledge to pass an entry level technical exam. There is a lot that is not taught at Dispatch school that you will only learn on the job. Don't sweat it. Know how to read METARs, TAFs, NOTAMs, PIREPs...pretty much any text weather. Review approach plates and perhaps en route charts. There are some good YouTube videos out there on the subjects.
Expect to answer some scenario-based "What would you do if..." questions. Be prepared to explain/justify your answer. Don't worry about trying to get the "right" answer as much as being able to justify why you made the decision you made. They're checking your thought process, not necessarily your knowledge. If your school didn't cover Ops Spec C055 Derived Alternate Minimums, and Exemption 3585 (mine didn't) look those up and learn something about them. And, as others have said, know something about the airline. You should, at a minimum, know their hubs, the aircraft type(s) they operate, their fleet size, and a bit of their company history.
They're going to ask you why you want to work for them. Have an answer to that question. My recommendation is learn as much as you can about the company history and culture. You will hopefully find an aspect of the company you like (if not, maybe rethink applying there) and you can use that to work-up a "why do you want to work here?" answer. Make sure the answer is company-centered, not self-centered.
Finally, I urge you to not think of the interview as something that you have to "pass". Obviously know the basic technical stuff, but keep in mind that this is your opportunity to get to know them too. More than once I've gone into an interview very excited, only to walk out thinking "WTF was THAT all about?" And don't be an empty vessel; go in there thinking about what you can bring to them, not what they can offer you.
Good luck to you!
Is it always SAN? Why not PDX or MFR or smth?
