Initially, tidal movement is paramount to a good catch because fish position themselves to feed differently depending on incoming or outgoing flows. When you are on the Delta, take mental notes when you get bites and when you don't. Put these notes on paper and you will see patterns of behavior based on subtle tidal changes.
Once you've determined tidal influences, focus on specific types of cover. Cover in our system refers to tulles, grass flats, docks, rocks and trees. An often overlooked element when spring bass fishing is the relationship between giving birth and wood. It is common practice by big largemouth mothers to rub against fallen trees and branches to soften their bellies for delivery. This same wood is also effective for ambushing unsuspecting forage during other parts of the year, so keep this in mind.
The third element to a successful day is bait choice and color. When the bite is great, you can throw most anything plastic or otherwise and get bites. However, fishing on the Delta, though usually good, is rarely off-the-hook great. Bait and color choices will even change from hour-to-hour, so stay in tune with your activity levels, and when you are not receiving the type of action you want, many times a subtle color or bait size change will produce.
Lastly, a general understanding of how high- and low-pressure systems impact the fish you are seeking will add to your success rates. Typically, bluebird skies are difficult fishing after the early morning. Fish retreat from the sun and seek shade in nearly all cases. Find locations with either tremendous amounts of cover or access to deep water. In both cases, fish can find the necessary elements to avoid the heat. Cloudy days are typically the best to fish because regardless of the season, fish tend to roam freely during this type of condition.
By thinking and observing you will catch more fish. It is not simply that the fish aren't biting on a particular day. Visit any tournament weigh-in and someone always catches a large sack of fish. And with few exceptions, the success of a particular angler is simply due to the ability to put the pieces of the puzzle together on that given day.