Clean out your cupboards
Don't hoard old clothes. If you only have a teeny wardrobe, change your summer and winter clothes over twice a year. Anything that's old, bobbly, or beyond repair goes in the bin! And there's no point in keeping things that are too small or cheap tops that might have been fashionable once but were only ever going to last you six months.
Keep a stock of quality staples, accessories and shoes that fit you and your style.
Paperwork
It's incredible how much space paperwork takes up. Bad news for throwaways: you do need to hang on to important documents such as payslips, bank statements, bills, certificates, job contracts, anything to do with health, pensions, tax and all that jazz. Some you hang on to for five years, but many of them you should never throw out, so get some big files with sections for insurance, tax, work etc, and put them all in order!