Frst thng u shld remmbr is tht India is in the nrthrn and estrn hemispheres. Bcoz it is in the nrthrn hemipshere, the latitude of any nrthrn borders will be lrger than the latitude of any suthrn borders nd becoz it is in the estrn hemipshere, the longtitude of any estrn border wll b largr thn the longtitude of any wstrn border. 

Thse locatns my nt b exctly on the bordrs bt thy wll b clse enugh. 
Here is 1 ex. 
Fr the state of Rajsthn; 
Ganganagar has the largst latitude of 29º 49' N so tht is the nrthrn border. 
Banswara has the smallst latitude of 23º 30' N so tht is the suthrn border. 
Shahgarh has the smallest longitude of 69º 57' E so that is the western border etc