"do u [sic]..."

One thing that will get you absolutely nowhere in fault-finding is laziness; you will need to be thorough & methodical.
So start by cutting out the "u" and make the effort - it's really not much effort - to write "you" properly, eh?

"... suggest me a good literature on fault finding?"

The works of Sir Arthur Conan Doyle...? ;-)

Seriously, fault-finding is detective work - you need to carefully examine the facts of the case, deduce the cause of the fault, and thence decide upon the necessary repair:

1. Determine what the circuit should do;
2. Observe what actually does happen;
3. Deduce what possible faults could cause the observed symptoms;
4. Conduct measurements, etc to confirm or eliminate the possible faults;
5. Having identified the fault, determine the necessary repair.
6. Verify that your repair has actually fixed the problem!

Of course, the worst sort of fault is the intermittent fault - which makes 2 and 4, and 6 particularly difficult! :-0

Hint: One of the commonest causes of intermittent faults is (as has already been menioned) the so-called "dry" solder joint - ie, where the solder has not thoroughly alloyed with joining conductors.
Typically what happens is that, when cold, the joint just about makes an adequate contact so that the equipment starts working. But, as the equipment heats up in operation, things expand and the contact gets worse & worse until the equipment stops working altogether. Then, of course, everything cools - so the contact is restored and it all starts working again, etc, etc, etc...

I've had just such a problem several times in the high-voltage circuits of monitors and TV sets; fortunately, this can often be seen clearly in a darkened room by just looking for the arcing! (you can hear it, too!)