G'day
Are you based north or south Sydney? Every beach will hold different fish at different times. I used to mainly fish the northern beaches, and the location depended on wind, current and beach formations like gutters.
The best thing to learn is how to spot likely gutters or holes. If you can get to a high spot off the beach wearing polarized sun glasses you will see these areas as darker water. But check every session as the water activity constantly changes the sandbanks, so a gutter or hole may be there one day and not the next.
The best time for salmon in my opinion is early sunrise and sunset, especially if those times coincide with a tide change.
Hope this helps, let me know if you want any more info.
Cheers Leo