Ok , I am not a lawyer But i started ordered some LAW books from flipkart and reading them , To help myself.
1. You should do the same , read lots of books.
Now coming to your technical query:-
304B
Note - There may be possibility that Judge can acquit person in 304B , But he can frame charges on 306 before pronouncing judgement, So your lawyer need to be very careful from beginning itself.
Special care need to be taken care with CRPC 313 statement of accused.
2 ways to crack the 304B or any case is in on technical ground and as well as on merit basis.
Where she died , in parents house or inlaws house. For 304B it is important to proof that cruelty happens just before the suicide, if you proof that no cruelty then you will get acquittal for sure in 304B.
Now how she died , She hanged herself or She was burnt or Taken poison .
Let say she Burnt, What her dying declaration said.
If the DR has stated and verified that she is fit to make statement . if Dr and Judge was standing there when she made Dying Declaration.
If she died because of burning , then when she was admitted to hospital.For how many days she survived in hospital. Let say she survived for 3 days , they definitely you can ask DR then if she might died because of Pain (In burn case there is technical term i dont remember , but yes people suffer from some disease in such cases where they were burnt and die after 3-4 days , they you can crack Doctor , he will definitely admit that she might died because of PAIN ) (Just try to find that technical medical term)
Just check her post mortem report also , Was she empty stomach or not ???? If she was not empty stomach and there is statement that husband had fight with her and then she slept...it will help you that as per post mortem she was not empty stomach...means she had food and actully no fight happened.
Now come to police , if police followed the right procedure , In-case she died because of Poison or burn or by hanging her self , they if police followed the procedure correctly, Who sealed the Clother/Dupatta/Poision Bottel to send to LAB for FSL report. If the IO says that it was done by let say a brother or sister in hospital sealed the things in front of him , then you can agrue on that there may be possibility of mistake and for sure court will agree to you.
Take care of Doctor cross , i DR used words MAY be or mAy not be , I am not very sure --- this will 100% help you ...Your lawyer need to be very smart for this , but this can be done for sure.