Allowed expenses as deduction

Hi,

I am a self employed person, I file ITR3 (Business & profession). I wanted to know what all official expenses can i take as deduction from my gross income. Expenses such as Travelling, Stationaries, Subscripttions, Client meeting cost (Cafes & dinners etc), softwares & subscripttion, Telephone charges, Internet Charges etc. Which all can i take it as deduction and what is the limit for each category... is there a table i can refer to?