I have a lab that is a good waterfowl hunting dog. The key is start early. Read books and watch videos before you get the dog that way you know what to do from the getgo. Richard Walters is the king of dog training. I recommend his books and videos. You will want to spend 10 to 20 minutes per day working with your dog. Preferably two sessions per day 10 minutes each. And do this for about the first 8 months to a year.
If you don't have time Training is usually about $500/month with a trainer.
I trained mine for the first 6 months, but wanted to have his skills sharpened up and sent him to a trainer for two months. He came back like a robot. Took him to North Dakota last month and he retrieved about 150 birds, and never came back empty mouthed. If you want info on who a good trainer is let me know