Some lots have restrictions on the type of house you can build, such as a two-storey or a rear loaded house if located on a laneway.
Make sure that you can fit your ‘dream home’ on the size lot you have chosen.  Ask the developer or sales person about any local planning restrictions that might dictate the percentage of the site that can be covered by a house, as that might limit your choices.
As part of the contract of sale you may also sign a document agreeing to abide by ‘restrictive covenants’.  These are used to achieve a range of outcomes for a development such as sustainability measures or aesthetics.
Restrictive covenants might include the type of building products you can use, colour schemes, fencing requirements, even down to the type of landscaping or plants you can use. Make sure that the restrictive covenants in the area that you are considering suit you and the home you want to build.