Do not automatically place the house squarely in the middle of the lot.
Why?
The house does not have to sit centered, perfectly parallel to the street, or shaped like a box.
Move it forward. Move it back. Rotate it. Shift it to one side. Make it L-shaped, U-shaped, courtyard-shaped, or wrap it around a pool.
Before becoming attached to a floor plan, determine the legal buildable envelope.
Find the front, side, and rear setbacks. Identify easements, drainage areas, utility corridors, waterfront restrictions, environmental limitations, HOA rules, height limits, and lot-coverage limits.
Then look at the neighboring properties.
Do you want your primary bedroom beside the neighbor’s basketball court or pool equipment? Maybe the quieter side of the lot is better. Does a second-story window next door look directly into the future bathroom? Could you use a garage or service wing as a privacy buffer?
Decide which rooms deserve the best locations. The kitchen may deserve the view. The primary bedroom may deserve the quietest corner. The garage probably does not deserve the best waterfront frontage.
Think about sunlight. Some rooms benefit from morning light. Others become ovens under western exposure. Outdoor spaces need sun analysis too.
Then think about flow: garage to kitchen, pool to bathroom, front door to living room, children to bedrooms, dogs to yard.
At this stage, do not obsess over room dimensions. Think in zones: private, living, service, outdoor.
Move those zones around on paper.
This is the cheapest moment in the entire project to experiment.