Comment on Taxation Simplified
Any expense that is incurred for trading is a deductible. In ITR form there are specific exenditure like conveyance, telephone, internet, electricity and a complete list which is available. Even if there are expenses which are not on this list, you have a section called other expenses, mention it on them.
Whatever you mention as an expense keep the supporting document or any further reference. You can maintain an excel sheet with a simple bank/cash book which show receipts and payments done for easy reference.
If you have not declared the losses in time for previous years, nothing much can be done about it. Make sure you start following it from this year, better late than never.
Cheers,