What is the best spot to actually catch fish and what to use??

If you have a boat, fish for sturgeon on the other side of the bridge near the old navy ships. Salmon roe wrapped with bait string works great. The staff at the marina bait shop will tell you what's working.

Fish between Martinez and Port Costa, use grass shrimp or ghost or eel or a combination worked best, deep water

Bait at the Antioch pier works well