If you don´t need it anymore, give it away or sell it on eBay. Don´t just throw it away. Minimize your rubbish at the same time. Always sort your rubbish. Use biodegradable products.
Textiles
In 2016, 100 billion pieces of clothing were produced for 7 billion people. The global distribution is highly unequal. For example, Germans on average bought 60 (!) pieces of clothing last year (German Greenpeace magazine 01/2017, p. 7). The other Western countries are not much better.
So: Buy second hand. Buy less.
Buy good quality (organic cotton). Every piece of cheap clothing comes with an extra-large load of water pollution.