(1) Spend a lot of time discussing accomplishments at their current / previous employers. If you drill down on particular projects they should be able to explain, in great detail, exactly what their contribution was and how they worked with the rest of the team to get that done.
(2) Pick a technical question that has a lot of depth so that you avoid false positives because people have just looked up the answer on the internet. I would also add that in my view the best questions have no tricks and require no "aha!" moments. It should be something the candidate can be reasoned through step by step so you can see their thought process. When they come up with an initial solution, then you can dive deeper by expanding the problem or adding additional constraints.