1. You really won't get good at identifying them in flight well until you get experience. You'd also ideally want to hunt with someone experienced for the first few times. With that said there are some guidelines you can follow. Luckily the few that have lower limits on are the easiest to distinguish. Pintail, red head and canvasbacks. Really study those. There are others listed on the photo below, but I've found pintail, redhead and cans to be the most likely ones you'll encounter. Wood duck is pretty easy to id
Cans are pretty obvious. They have a large red head/neck and white body. They are a big duck and have bill that is also pretty distinguishable if you'll look at some photos. Limit 2
Pintails have a longer neck than any other duck and the white stripe that comes up the neck and onto the head is pretty distinguishable. In my area they also really like to circle and not commit. You can pick out the pintail feathers as well. Limit 1
Redheads are easy to identify but somewhat hard to explain. They obviously have a bright redhead as the name implies and a grey body. Body shape is similar to a ringer but you'll know the difference because they have a much lighter body. Ringers also have a very distinguishable contrast is color from the dark wing and lighter belly.
The hens are much harder to identify and I don't think anyone can tell one apart from a ringer hen in flight. You should assume any hen with a drake is that same species. Limit 2
Your other species for the most part all have a combined limit of 6 except mallards. Mallards are easy to identify though.
You can use your phone to double check yourself after you've shot one.
Ducks typically fall into two categories: divers and puddle ducks. Divers generally like deeper water and as their name implies, they dive for food. Puddle ducks generally like shallow water and feed at the surface.
2. If at all possible find where they are coming in at and be there waiting for them before they get there. Get in and settled about 30 minutes at least before shooting time. This is often the most enjoyable time for me. You can relax, enjoy a cup of coffee and listen for the wings, whistles and quacks as they start pouring in. Ducks in general roost in one place and feed in another. You shouldn't even need decoys if you know where they want to be. However, I always have at least a half dozen out. It could help you pull in a few that might not want to be right where you are.
3. Duck is nothing like chicken or upland birds. If not prepared correctly you most likely will not like it. Go to honestfood.net and there is everything you need to know about how to prepare and cook duck properly. I really suggest following some of those recipes but I also like to make duck poppers as well just like a dove popper. If only taking the breasts you just peel back the skin and cut out the breasts.
In general your puddle ducks are better eating and divers are not as good.
However, there are exceptions. A canvasback is considered a diver duck but in my opinion is the best eating duck there is.