Put at least two fully patched ethernet outlets in any room. Create an infrastructure star with a centralized "server room".
Make sure to have enough power outlets in each room. Check wire quality and fuses.
For sensors you want to look into 1-wire technology. This is the cheapest way to measure temperature or count usage of e.g. water, natural gas and power.
Think a lot about energy and consumption like heating support with solar thermal water heating or insulating the whole house.
Also check tubes and water outlets.
Consider the need of security elements like sensors and cameras. Power over ethernet might come handy.
Look into combined house automation technologies like Konnex/EIB or EnOcean or z-wave. But be aware, this stuff gets expensive.
Welcome to a never ending playground.
I suggest you start implementing stuff that saves you money, like optimizing your energy consumption and monitoring that.