Dead stock is money sitting in products that are not moving. Start with the items that have been held longest, have low sales, or occupy valuable space. Compare their buying cost, selling price, condition, and likely demand.
Use sales and stock records to distinguish a temporary slow period from a product customers no longer want. Consider a targeted bundle, clearer description, revised price, or a decision not to reorder.
Do not discount every slow item automatically. First understand why it has not sold and whether the promotion will still protect cash and margin.