Though there are many important factors that all line up to produce a good duck hunt, these are the 3 most important in my opinion:
1. Understanding of Duck Biology and Behavior. If you know your ducks and their habits, and how they change given the weather conditions, time of year, abundance of feed, etc. then you will know how to plan more successful, adaptable hunts. This is the most important thing there is. A lot of this is book knowledge, but you can never replace days in the field hunting and scouting... bringing me to my next..
2. Scouting and Location. Know what your target birds and doing inside and out. Know their roost, their feeding areas, their loafing areas, when they fly off, when they come back, and when they change plans. Scouting is not just for before the season, it is a constant priority. In Oregon we get a large population of wintering cackling geese that will hammer the same field for several days numbering in the tens of thousands, obliterate the crop being grown in there, and move on to the next field. If you are on the field the birds want to be in at that point in time you can have the hunt of your life - but if you are on the field that you want to be in you'll painfully watch birds elsewhere all day. My point is this - birds change plans often and going to a place that you saw birds in a couple weeks before simply won't do it a lot of the time.
3. Weather. Knowing what the weather is like in your area as well as the areas around you will help you anticipate migrations and predict local bird movements and activity. A sunny, bluebird day is not always a bad thing if you know how the birds change on days like this. It is when you need to be adaptable.
5 barrow's ge
2 l scaup
1 g scaup
1 comm ge
TOTAL DUCKS = 132
TOTAL GEESE = 83
TOTAL WATERFOWL = 215