There is a lot of similarity between Vaastu Shastra and Feng Shui. Feng Shui also recognizes the existence of Yin and Yang (positive and negative forces).

History
The word Vaastu is derived from 'Vastoshpati' used in the Rig-Veda, and is meant to provide protection, happiness and prosperity. According to our Vedas, Vaastu Shastra was originated, taught or preached by 18 different individuals. These are: Brahma, Narada, Brihaspati, Bhrigu, Vashishta, Vishwakarma, Maya, Atri, Garg, Kumar, Nandish, Nagnajita, Vishalaksha, Purandara, Shaunakh, Vasudev, Anirudh and Sukra. One of the most popular stories behind the origin of Vaastupurush is as follows:
Lord Shiva had killed a devil named Andhak. A spirit came out of the perspiration of Lord Shiva and consumed all the blood of the devil. His hunger was not satisfied, and undertook penance. Lord Shiva offered him a boon. But the spirit went wild, and terrified men and animals. 81 Gods including Lord Brahma laid the spirit face down, and they then sat on different parts of its body. When the spirit asked for forgiveness, Lord Brahma offered him a boon," After building any structure, the people who offer you prayers and worship you as vaastudevta will be blessed with pleasures and prosperity. However, those who do not offer you prayers shall be at your mercy."

Although the science of Vaastu Shastra evolved during Treta Yug, written evidence dates back to a more recent 6,000BC. Sage Kasyapa wrote the Kasyapa Silpa the first official treatise of Vaastu. In the treatise Agama Shastra, which explains the science of temples, Vaastu is considered as the basis of any construction. Even the excavations at Harappa and Mohenjodaro also indicate the influence of Vaastu on the Indus Valley Civilization.

Basic theory behind Vaastu Shastra
Everything in this world is made of Five elements (earth, water, fire, air and space). The principles of Vaastu Shastra are mainly dependent on the arrangement of these five essential elements. There are five basic theoretical factors behind Vaastu Shastra:
1. Solar Science: Depending on the distance between the Sun and every point on earth, there is preponderance of positive or negative rays, which affect our physical and mental health. For instance, morning rays are considered positive rays, and afternoon rays are considered harmful. Your home is static, and so should be designed in such a way that windows and all sources of ventilation absorb as many positive rays as possible. In India, Northeast is the best direction, and South West is the worst. Thus, rooms where you will spend most time should be facing the Northeast. Note that this rule is not necessarily applicable for North America or other continents, and should be adapted keeping the theory in mind.

2. The earth’s magnetic field: Blood contains hemoglobin, which contains iron. Since there is iron in the blood, magnetism affects its circulation. If the collective magnetism of your body is taken into account, your head is the north and feet south. So, when your head is facing towards the north, like poles repel and the blood circulation to the brain decreases. If the head is towards the south blood\flow to the brain will increase. During sleep, you require minimum circulation. So, Vaastu says that when you sleep, ensure that your head is facing neither north nor south ( i.e. it should face east or west.)

3. Wind or Pawan: Breathing fresh air is beneficial to good health. Your house should channelise wind by positioning the ventilation points correctly. This is also dependent on the topography of the surrounding area. Atmospheric pressures or the changes in it also affect wind. So, careful study of the environment is necessary.

4. Law of Gravitation: You are constantly being pulled to the center of the Earth. The force pulling towards the center of the earth is also concentrated at the center of the object. Your house is also an object, and within your house there is a point which acts as the center of gravity. Laying excess pressure on this point by placing heavy objects could be detrimental to the structure. Vaastu Shastra says that a courtyard is advisable as the center point of the house.

5. Cosmic Forces: This last factor links Vaastu Shastra to astrology, which considers all planetary positions and distances. Vaastu Purush (energy) Mandala (astrological chart which relates to the layout) dictates the site planning.

Basic guidelines of Vaastu for your home and good health:
1. Orientation of premise - north and east, since all positive solar energies come from this direction
2. The shapes of premise - Square and rectangle are the best shapes. Triangular shaped plots is considered inauspicious. A small narrow plot between two big plots is also not good. If there is more open vacant space in south than in north, it will lead to downfall.
3. Angles- All the angles should be 90 degrees.
4. The entrance door of living/dining room- north and west are best, east is also considered good. The living/dining room itself should be in the northeast.
5. TV/music should be in the southeast, as it generates heat
6. Dressing room- should be in the southwest, as it includes use of mirror.
7. Telephone- southeast, east and north as it results in effective conversation
8. Location of kitchen- southeast, east or south are considered best. Any equipment, which generates heat or electricity, should be in southeast or south, which are the best locations for the cooking range. It should never be in northeast or north.
9. Location of bathroom/toilet - Basin should be facing north or northeast. Water closet should be West or northwest. Water heater should be southeast or south. The bathtub should be north or northeast.
10. Location of the bed (your head)- east or west is also fine. A couple's bedroom should be south or southwest, preferably on the upper level. Children's bedrooms should be in the east or southeast. Guest's bedroom should be southeast or west.
11. Storeroom should be south or west. Southwest is also good. But keep northeast vacant or light. Study Room should be facing east, northeast or north. You should face east while reading or writing. Pooja Room is always best in the northeast corner or near it.
Pictures and scenes of war, battles, demons, pig, leopard, tiger, jackal, serpent, eagle, owl, pigeon, hawk, crow and crane are inauspicious.

Further research and reading
The above gives you a very general introduction to this vast body of knowledge. If you are seriously interested in evaluating your home or office, then you may read scores of books available in the marketplace, and many websites have also cropped up. The best solution would be to engage a vaastu consultant who can help you with the layout of your home, and also help you with the interior decoration.