• Iemand blij maken met een dode mus
  • Literal Translation: "Make somebody happy with a dead sparrow."
  • Meaning: "Promissing someone something great, that finally seems worthless"

• Iemands rechterhand zijn
  • Literal Translation: "Being someones right hand."
  • Meaning: "Being indiposable to someone."
  • English equivalent: "Be someone's right hand man"

• Iets op je lever hebben.
  • Literal Translation: "Having something on your liver."
  • Meaning: "Having done something wrong which could get you into trouble."

• In het land der blinden is éénoog koning."
  • Literal translation: "In the land of the blind, one-eye is king."
  • Meaning: "Where none can do something, the one who has even a little knowledge has the power"
  • English equivalent: "In the land of the blind, the one-eyed man is king"
  • English alternative: "(being) a big fish in a small pond"

• Ieder voordeel heb z'n nadeel.
  • Literal translation: "Every advantage has his disadvantage."
  • Meaning: "everything that has an advantage in one way also has a disavantage in an other way."
  • Actually a quote from Johan Cruijff, but it has become proverbial.

• Je kunt beter over je fiets lullen dan over je lul fietsen.
  • Literal translation: "It is better to talk shit about your bike than to bike on your dick."
  • Meaning: "If you plan to talk nonsence it is still important to be aware which words to use."

• Je moet verder kijken dan je neus lang is.
  • Literal Translation: "You need to watch further than the length of your nose."
  • Meaning: "You need to take a look at the problem carefully, you need to search the cause of the problem. And not at the effects of it."

• "Jong geleerd is oud gedaan."
  • Literal Translation: "Learned when young is done when old."
  • Meaning: "Something learned at an early age will be easy when one is old(er)."

• Krakende wagens lopen het langst.
  • Literal Translation: "Creaking carts last longest".
  • Meaning: Objects which seem to be near collapse, often end up lasting much longer than expected;
  • Old people suffering from little diseases often live the longest.

• Kleine potjes hebben grote oren.
  • Literal Translation: "Small pots have big ears/handles."
  • Meaning: "Adults must be careful about what they say within the hearing of children.
  • English equivalent: "Little pitchers have big ears"

• Kleren maken de man."
  • Literal Translation: "Clothes make the man."
  • Meaning: "Good clothing adds to a man's stature."
  • English equivalent: "Clothes maketh the man."

• Knollen/Appelen voor citroenen verkopen.
  • Literal Translation: "sell beets/apples as lemons."
  • Meaning: "Presenting something as something else which is more valuable."

Source: http://en.wikiquote.org/