How does boot animation affect booting time. And how can I decrease the booting time? What if I load a lite boot animation in my device.
Does is decrease the booting time?  

And how to decrease booting time as well as improve my phone's features.

device: Samsung Galaxy y duos GT-s6102
OS: custom ROM XDV3 by XDA Developers
BootAnimation doesn't affect boot time. It's just a series of pictures shown in sequence to you, while your phone is ready to give you the GUI.

There is no one certain recipe to make your phone boot twice as fast. Check this and this for possible solutions, to make your phone boot up faster