Depends very much on the type of venue. Shallow surf beaches often best either side of LW in my experience. Steep-to ones better towards HW. But my best local codling of 6.5lbs (good un for N Cardigan Bay coast) came on the 4th hour of the ebb on a steep-to beach that becomes a shallow surf one at low water. I only knew I had a chance of getting one because the night before I'd lost a good fish at the same time of the tide, and reeled in a 6-inch rockling that had swallowed a 3/0 Viking hook. Therefore, a larger fish had attacked it as it swam by at that stage of the tide, obviously looking for big snacks. So, next night as soon as I (deliberately) got another wee rockling, out it went as a livebait and BINGO!
Key to it all is get out there, fish as often as possible, watch what happens, keep notes and whatever patterns emerge, follow them and you will catch fish
I hope that helps - it has helped me more than any book money can buy. The marine environment is the best book there is - enjoy the read, I know I have!
Cheers - John