Hello Harish, The best I can tell you is to get online to You-Tube and try and watch some of the Maya Lighting tutorials. Without knowing your specific task it's very hard to answer your question thoughtfully. Lighting basics in Maya is pretty simple to ultra complex, so it's best that you start with simple light construction.
To get better with lights, create an object (sphere,cube) and a ground plane. Then create one of each type of light. Move the light around and play with it's level intensity, and watch how it reacts with your objects. Try placing a light inside and outside of an object. Play with all the settings and really get to know how to move, rotate, and dim lights. Try lots of lights together and set different angles and positions in the scene. Concentrate on this exercise for quite a while. You will soon get the hang of what each light does.
As well, you should read in the documentation from Maya. Don't give up! STU