What do former volunteers say?
Try to make it clear to yourself what you need to be well prepared for starting your project. This is different for everyone, one wants to know exactly which items he/she needs to pack, the other wants to know a lot about the country and the project. If you know for yourself what is important for you to be prepared for, you can ensure that you obtain that knowledge as far as possible. Remember that you can't prepare for anything, so don't try to worry about it!
Very nice site! As a volunteer, I did not immediately think of the negative impact that I could have for the population, after all, I was helping. I wish I had known beforehand how important good preparation is, then my impact would have been greater on my project!
Buy the essentials for travelling. If you forget something; no worries: you usually need much less than you think.
I always like to reflect on Dutch culture before leaving. Eat stew again, cycle through the meadows, chat with your family about the norms and values that you find important. By being aware of Dutch culture, you can often better place abroad why you react as you do with cultural differences.