Obstructions or Veedhi Sulas are said to occur when roads approach the site at a perpendicular. Some of these are considered bad while the others don't matter much. By and large, any road from which one can look directly into the house is naturally not desireable. Now since the house is preferably in the south and west, that makes some very specific roads "inauspicious" according to Vastu pundits.

The solution is, if possible, to shift the house plan slightly if you haven't already built it. In an existing house or on a small plot, the suggestion is that you shift the main gate and preferably raise the compound wall in front of the approach road. In any case, it is better to have your main gate away from a junction.

AND HERE ARE THE SUNDRY HEADACHES

Water Bodies: Wells and underground tanks should be in the north and east of the site because (hopefully) it is also the lowest corner. This way, all the water that is bound to be spilled around it, will not muck up the rest of your garden. Overhead tanks on the other hand are best placed on the south-west which (again, hopefully) is the highest point of the building, thus maximising shade over the house.

Garages and Servant's Quarters: You are advised to have them in the north-west or the south-east corners, preferably without touching the north or east boundaries, in general accordance with the rule about the location of open spaces.

Main Entrance: Ideally, this is located in the north-east sector so that the rain cannot blow its way into your house. Besides, if that is where you have your garden anyway, it would be the most pleasant way to enter a home.