Hubby and his family are all in the building trade.
Be there everytime a new trade starts. ie when the plumbers come in for the first time, go right through the hose with them, every tap, floor waste, vent and drain.Make sure you have all of your fixtures and fittings ordered, and make sure they know what is going where. Same for the sparky, every powerpoint, ceiling fan, every fitting for every room,and BE THERE ON THE FIRST DAY THEY START.
The majority of stuff ups are clients not stating they wanted specific types of floor wastes/exaust fans/taps. The plumber goes in and mocks up for one setup, the tiler/plasterer goes in and does their part and then the owner says "oh no, I wanted XYZ type of fitting" and the wall has to have holes punched in it, or tiles need to be pulled out, which results in other tiles being cracked in the process blah blah blah.
Have everything chosen well ahead of time.
Try not to be working full time while you do it either.
Building is a full time job on its own.
GL