to crack wbcs you need to focus more on indian history,geography,polity .follow this site for wbcs and also wbssc exams like kps,ldc etc .lets start with modern history as it is one of the most important part to know.I will suggest you to complete modern indian history first as it has 25 marks in wbcs exams.

head quarter of 

portuguese east india company- coachin,goa

dutch east india company - pulicut,bengal

english east india company- surat,masulipattanam,madras

french east india company-surat,pondichery

In 1690 JOB CHARNOCK founded sutanuti factory of bengal.

In 1700 FORT WILLIAM was established.

faruksiyar's farman in 1717 gave the rights of duty free trade in bombay and madras .it is also known as MAGNA CARTA of companies trade in india.

battle of PLASSEY 1757 between siraj ud dullah and east india company. siraj was defeated .

battle of buxar-1764,hector munro was company;s army's incharge

DUAL system in bengal started with TREATY OF ALLAHABAD in 1765.

fisrt governor general of benagal warren hastings ended the dual system in 1772.

hi friends ,you will find that there are not many resources for preparing online for wbcs,wbssc like exam .for upsc there are many sites ,yes you can make a good base by reading them but wbcs exam is quite different in nature,it generally ask straight forward question.