To kick off the build I like place 90x45mm pine around the whole perimeter of the property at a level around 500mm from the top of the finished concrete slab / floor height. This is to setout the home. I also get a Building Surveyor to place the exact corners of the property onto the timber to make sure we start with the correct placement and measurements. You'll be surprised how many fences and parts of peoples homes are not on the correct property.
When preparing for the engineering plans you will need to organise a soil test to check the stability of the soil for building.
An important point to remember if you are building a basement is to have the testing done deep enough for the basement piling, usually around 6 to 7 meters in depth and in a few different spots because even on a small piece of land the ground conditions and water table can vary greatly.
The start of a new build in existing areas usually starts with demolition of the existing house. At this stage it's good to establish with the neighbours the existing fence lines and that they are in the correct place.
Also any existing walls on the boundary that are part of your garage or house that need to be demolished, these will need extra attention as it will leave both properties open to each other and the neighbours may have installed clothes lines, hot water units or sheds connected to those walls.
Once organised the demolition should take around 3 days to complete onsite.