According to Vastu Shastra for rectangular shape of plot is the best plot. Here is not show that your front of which side ( 40 feet ) . If it is towards East and West side than you should construct building 40*50 feet / 40*60 feet and 40*70 feet.The length of North - South is longer than East - West. It is best quality of plot.
You should build the main entrance as following map
You should divide the Northern side in eight parts then 5th and 6th part suitable for main entrance. You should follow the following tips for construct home.
Room ----- Directions
Pooja room ----- North East
Kitchen room ----- South East
Bedroom ----- North North West, South and North North East.
Store Room ----- North West.