I'll first tell you what geneology is, then I'll tell you about resources you can use for such a research in the Netherlands, and at the end I'll tell about a few problems or remarkable cases I encountered.
In geneology there are two ways of investigation.
It's possible to search for your family tree, which means you will find as much data as possible of everyone with the same surname who is related to you.
Or you can do research to get your pedigree tree. You could call this your family tree of your genes, because in here you'll find your parents, grandparents and so on. People in a pedigree don't have same surnames as people in a family tree.
Write or talk with your family who are still alive to get information about them and about their parents. In this way you can collect data about eighty years from now. To get data from before this period you have to go to an archive.
In the Netherlands you find four types of archives:
In the Central Agency of Geneology they have copies of almost all existing documents from the whole country. They have also a large amount of 'pray pictures' (bidprentjes in Dutch) and advertisements of announcements.
In the State Archives you find originals or copies of documents from and about a province/state. The State Archives can be found in the main cities of the provinces.
In the City Archives you can find documents from a city and in the Region Archive you can find documents from a number of smaller cities.
Starting at 1795-1800 there is a law which demands that births, marriages and deaths must be declared at the so called Burgelijke Stand. Because of this you can find birth-, marriage- and death-documents. Those are in general easy to read. From this period on you can also find family-documents with profession, religion, address and the dates of arrival or department out of the city if any.
Before 1795 you have to use so called DTB-books. These are the Baptism-Marriage-Burial-books of the churches (in dutch: Doop- Trouw-Begraaf-boeken).
Around 1680 it happens sometimes that documents don't exist anymore. One of my own experiences was that over a period of 50 years there were no documents: those were probably destroyed by some bombs in de Second World War.
When there are no DTB-books available anymore you can still check the notariële archieven. In here you find documents like last will documents and so called erfdelingen.
From now on till 1800 you have enough if you know Dutch. I can
imagine that this is for people outside the Netherlands a huge
problem, but don't despair! You can always ask help in the archives.
They can even do the research for you for a small fee.
Between 1795 and 1813 it is possible that you encounter documents written in French, because the occupation of The Netherlands in that period by Napoleon.
I told you already that the so called Burgerlijke Stand started in 1795/1800 and I can tell you now that it was Napoleon who started it.
In the DTB-books the text is often written in older Dutch, but also in Latin.
Knowledge of some languages is certainly not a disadventage!
Not everyone could write in earlier days. It was the pastor or referent who wrote about the baptism, the marriage or the burial. Change of referent or pastor is often noticeable on the also changed spelling method. Surnames changed! I encountered for instance the surname Kalf also as Calf, Calff, Kalff en Calv.
Normally marriages of this kind were not allowed, except when both families and both churches gave their permission. I found for instance a marriage with two "before marriage"-documents. In the first one the father of the bride wouldn't give permission for the marriage, in the second one he gave his permission.
In so called erfdelingen - in which is described who what gets after the death of both parents - you can find data about how much land the parents possessed. But a hond (in English: dog) (which is 14 acres) and a morgen (in English: morning) (which is 85.16 acres) don't say much these days. Why did they use no standard measure system? The Metric System has entered the Netherlands in 1799, again by Napoleon.
Most of the time the land did also have names. Often a name which describes the form of the land, e.g. Breeakeren (wide farmland), het Lang Camke (the long field). The name could also point to how the land was situated, e.g. de Poelkens (the waters).
It was a habbit to add the name of the father behind the name
of the child. This happened especially with common names like Jan.
You could get something like Wouter Jan Hopmans. The name given to
the child was Wouter and his the name of his father was Jan.
A difficulty which you can encounter is that in the baptism-document you'll find the name without the patronymicum and in all other documents with the patronymicum. This can be confusing: have we here one person or two persons?
Literature: Empel in het byzonder by Jacques de Bekker (1993).