We had to fit co-ax sockets in each room, and phone points. A neighbour who didn't want either in her bedrooms had to sign a disclaimer because anyone buying the new house in future was entitled to expect it to conform to the regulations at the time it was signed off, and hers would not, so the Consuel had to make it clear that it hadn't been his omission.
We also ran Cat5 cables around the house with network points in every room and the garage and a patch panel in the store room, because we need all the broadband performance we can get, and wifi has a lower maximum speed (more so then than now). Then came the CCTV cabling. The hardest part is knowing what new technology will need in a few years' time. If I were starting now I'd have HDMI points and a wireless speaker system too!
If you need basics to start with, fit lots of breakers serving one or two sockets, you can then wire more sockets into these original ones in future up to a max of, as I recall, 6 or 8 sockets per breaker. The Consuel has to check you have enough breakers for the number of sockets, he isn't bothered if you have allowed for future expansion which may not happen. I forget what the minimum numbers of sockets are for each room - check on this.
We have a column of cupboards on each floor with holes in the concrete floors where pipes, cables and tubes pass down from roof to ground. This has been our best design decision! Only yesterday we ran cables down to control tube heaters under each floor's water manifolds, connecting to a thermostatic socket on the ground floor, to ensure the pipes don't freeze while we are away! Without these, everything could have been hidden behind plasterboard and we wanted all services easily accessible.
By the way, changing the subject a bit, plumbing in plastic tube is fairly easy DIY once you buy the compression kit (around 60€ from Bricomarché). We did our own laundry room a couple of years ago with washing machine, sink, loo, shower and its own hot tank, all in plastic tube.