It is important to start organizing the financial situation well and to inform yourself about what to consider when building a house compared to buying a house. I only really started doing this after we had the approval for a plot of land and in retrospect I am relatively glad that some of the houses we looked at did not work out. And also that the building areas were already full at the beginning. Otherwise, there would have been a significantly higher risk of making a miscalculation in the order of €50,000 due to ignorance. And that would almost certainly break your neck.
A plot of land with a developer commitment, for example, means that you have no choice with the construction company. After you have bought the plot, you are obliged to build with them. No matter if the standard tiles are the cheapest ugliest junk on the market and the alternative costs €100 per square meter. If you decide on a developer plot, you must also know that you can build a house with this company within your budget that you like. Therefore, under no circumstances sign for the plot first and then look for a house from the catalog.
Also, think a lot beforehand about what you want. Which rooms must the house definitely have? Do you need a basement (very expensive in new construction)? How much garden do you need, how much is too much? How many square meters do you need? All of this applies to new builds and existing properties, and even if you end up continuing to rent, it will help you find nicer apartments.