There are several factors that influence the value of a painting. The primary factor is the value individuals or entities are willing to pay to acquire the painting. In other words the value is determined by what the market is willing to bear for the painting. This, of course, is directly correlated with the acclaim of the artist and the availability of the artist's paintings. Through the years, several artists have been masters of the craft during their time; of these some have pioneered new styles, schools and directions in the art of painting. This achievement creates high benchmarks for the artists of that time, and in turn puts a high value to the artist's work that pioneered the new direction. The spirit of pioneering and leadership are not the only criterion for valuing an artwork. The technique, composition and integrity of the painting are essential. This aspect, however, is taken for granted if the artist is a master in the field, but does play a part in differentiating paintings by the same artist. With contemporary artists, it is often their ingenious interpretation of the world around them and their style and technique of portraying that world that excites art buyers and in turn raises the value. Quite often the period, subject and circumstances under which the artist painted the work plays a role in determining value. Every artist has a "golden period" in his or her career, and paintings from this time are quite often valued higher. Also, the emotional attachment and the relevance of the painting to the artist itself plays a role in value. All said and done, the value you put on a painting should determine its value. What you see in the painting, the emotions it conjures up within you and the feelings it evoke are often the best determinants of its value.
Like all rare, unique collectibles, a secondary market for trading these objects is developed over time. In the world of art, this market consists of galleries (on-line and off-line), auction houses and individuals. As long as the work of art you own has an inherent demand in the market, there will always be an avenue to sell it. This varies depending on the artist's acclaim, the country of origin and the strength of the secondary market in the region of sale.
Getting started is not as difficult as it seems. It is simple and can be extremely enjoyable. The easiest way is to spend some time browsing through saffronart.com or other Indian Art sites. Through the process, you will be able to learn many things, and in time, you will be amazed at how much you have learnt. You could read books on art, talk to friends who are familiar with the subject and visit some Museums and Galleries in your city. Just walk in to a gallery, admit your unfamiliarity with the subject and ask the gallery manager all the questions you want. There are many gallery owners and managers who enjoy talking with people who want to know more about art.
The best place to start is the Art Glossary in the Art Guide section of saffronart.com. Reviewing the glossary will give you an overview of the commonly used terms in the art world. Additionally, don't be afraid to ask questions at art related places (like galleries and museums); the more you are around art, the quicker you pick up the "art-speak."