Training is simple!

Do's and don'ts courtesy of trainer Barbara Haupt (Spanielsinthefield.com).

• Keep voice commands to single words, say them once, and never give one you aren’t willing to enforce. That may mean putting on your ogre face, going after the dog and bringing him back to the site of his sin.
• Don’t use the dog’s name when giving commands – only the command word.
• Use hand and whistle signals.
• Practice on yard drills using a long check cord.
• In the field, sometimes you must forget you’re a hunter when a few minutes training will serve you better.
• Save your loud voice for the most serious of sins.
  

And the vocabulary that Haupt says every dog should know

• His or her name
• Hup
• Here
• Hold
• Leave it
• Heel
• Good [ed: and "no"?]
• Back
• Over
• Kennel

That's all there is to it.