When making presentations you should get swiftly to the main theme. While you should not understate the benefits of your proposal, avoid exaggeration, showmanship and marketing gadgets. The basic rule is to be professional and substantial without a great amount of waffle, known as poespas in Dutch. Unlike in some other countries, humour is not an essential part of any presentation, although if it is well used it has its place. Avoid interruptions during presentations unless you have an urgent question concerning the information that has been presented.
Dutch negotiators tend to be persistent and tenacious.
As with many informal cultures, when they start to raise their voices it is a sign of genuine impatience. Be careful, as this behaviour is likely to be counter-productive. Dutch negotiators tend not to like haggling, so initial quotations should be realistic. Here it is important to legitimise your bids with comparative market prices or other available parameters. Nevertheless, the offer should have the scope to cover margins, unexpected developments and some concessions.