When a person is born, the planets at the instance of birth have to be in one of these signs, and in turn would be in one of the four elements. For example, if Moon were in Libra, it would be occupying an Airy sign. As such with the other planets.
The planets considered in Vedic astrology are: Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn and the two shadow planets Rahu and Ketu.

Take this example.( Date of birth - Oct 11, 1942)

Out of 9 planets 5 are occupying signs that relates to the element Earth. There is a greater percentage of the EARTH element in this sign and thus we can say that the RULING ELEMENT for this person is EARTH.  In many horoscopes you might end up with an even distribution of the elements. In such cases more than one element tends to influence the likes/dislikes of that person.
 

Once you have concluded about the ruling element in a horoscope, you can make a fairly good astrological analysis about the likes/dislikes of a person. In many horoscopes this cut and paste method might not work because of other strong modifiers.

Fire
(Aries, Leo, Sag)
Majority of the planets occupying the fiery sign in a horoscope tends to makes a person bold, assertive, enthusiastic, pushy, adventurous, sporty, fond of outdoor activities. These are also the keywords to understand the likes, dislikes and basic temperament of persons ruled by the element FIRE.

Preponderance of the FIRE element makes a person very generous. All Fiery signs have child like innocence and take great delight in giving/receiving gifts. Price tag for a gift is not a big concern. Your status is seldom a criterion with them when buying a gift for you. They would not appreciate gift advice from other persons; they are self-assured, about their gift ideas and repudiate any criticism about it.
Fiery signs seldom care about the price tag. They have no patience for bargains. And they make impulsive purchases on credit.
Fiery signs would almost always appreciate branded merchandise, bold and bright colors, things and objects related to sports, adventures, and outdoor activities. A formal dress is a bad gift idea for fiery signs, however, branded (bright color) outfits for a skiing or a mountaineering session would have them think “How does this person know that I like this kind of stuff?” A VIP Season pass for an exciting game, gift certificates for adventure resorts, contemporary fashion items with striking colors will have them remember your thoughtful gifts for many years.


Earth
(Taurus, Virgo, Capricorn)
Majority of the planets in the Earth elements makes a person down to earth, practical, premeditative, methodical, economical, and prudent. Earthy signs carefully weigh the merits / demerits of a gift, and they would not buy a gift unless they have bargained to their utmost satisfaction. Earth element rules material pursuits, therefore giving/receiving gifts is a well thought out plan in terms of utilitarian value of a merchandise and also good return for money.

Successful businessmen, planners, bankers, financers, investors must have preponderance of the earth element.
Anything that has a long lasting value makes tremendous sense with earthy signs. Earthy signs will have all the patience for spotting the right gift. They can spend long hours in the mall without getting exhausted. Spotting a gift items with decorative and trade off value – this ability comes naturally to the earthy signs. No one can beat them in this game. Costly jewels, gems, stones, furniture, paintings, and also collectibles such as rare coins, manuscripts, antique items fascinate them.
Your Earthy friends already have many of the conventional gift items you planned for them.
Earthy signs are not amused by the Surprise Gift idea, they want to be sure that the money (even if it is yours) is spent judiciously.  So ask them what they need, or to be safe - Gift certificates for household items make tremendous sense to them.
A fully paid maid services to clean the remotest corner of their house, or a paid landscaping services to decorate their backyard are some great thoughtful gift ideas for Earthy signs. Earthy signs decorate their houses with taste and meticulous planning.  If Earthy signs predominantly rule your kids you might want to gift them a Savings Account or an Investment for the Future.



Air
(Gemini, Libra, Aquarius)
Persons with preponderance of the Air element will be intelligent, having fertile imaginations, well informed, literary and innovative. The air element is responsible for birth of intellectuals, great scholars, orators, inventors, scientists etc..
Airy persons can be very creative and thoughtful about gifts. In fact, most of the new innovative, sometimes crazy and whacky, gift ideas that float in the market come from them.
Airy persons are restless and inclined to experiment with new things. They are far ahead in fresh ideas and new thoughts. In giving / receiving gifts what drives them is an ultra modern, innovative, new, queer, imaginative objects. Conventional gifts bore them tremendously. Cost is not a criterion; innovation is.
Airy signs are eternally curious. Novel and innovative things hook them. Books (most of those they already posses or have read), stationary, unconventional electronic gadgets, experimental fashion, and science objects fascinate them. A telescope with queer buttons and a guarantee to "spot the UFOs" would be an instant hit with them!
Stores selling that kind of merchandise might be the right place for buying a gift for your Airy friend. When you browse in a mall and come upon whacky and strange things and murmur - “Why would someone buy that?” - well, those are for Airy signs.
You have to be really imaginative and spend hours on the Internet in order to spot the right gift for your airy friend.



Water
(Cancer, Scorpio, Pisces)
Watery element makes a person philosophical, imaginative, restless, ever dreamy, deeply spiritual, romantic, superstitious, contemplative, psychic and emotional.
Religious leaders, mystics, poets, artists, psychics are born under this element.
To truly appreciate the essence of a watery nature you might want to read The Gift of the Magi. O. Henry's classic short tale of giving and receiving. There is a karmic unbounded generosity that drives the Watery disposition.

Watery signs are genuinely concerned about the well being of others on a spiritual level and this is what drives their idea for giving / receiving gifts. They are not spendthrift and impulsive such as fiery signs.
Holistic items, natural food, organic items, yoga related items, auspicious items to bring a stroke of luck, merchandise that reminds them about the spiritual journey of the soul, books on philosophy, or classical music  are meant for watery signs.  Cruise to distant islands, meditation resorts fascinate them.
A strange sense of material insecurity haunts watery signs. Fashion, clothing, or decorative items that ‘hugs’ them into a psychological security would be highly appreciated by them (e.g. Curtains). They are fond of creating a cozy environment in their homes (e.g. Carpets). 
Charity is their birthright. Any kind of annual charitable donation on their behalf could make a great unconventional gift idea for watery souls.
Watery signs are very sensitive about giving gifts, so don’t forget to thank them multiple times for their gifts.


Kailash Khandelwal