Secondly separate summer and winter clothes and ones that could fall into both categories I.e thin twinsets. If you are really short of space use those vacuum pack bags that suck all the air out and leave things a quarter of the original size.
Thirdly, look at what you have left. Get rid of anything you don’t like, anything tatty or past it’s best and finally anything you haven’t worn last season.
If you need motivation read The life changing magic of tidying up: the Japanese art of decluttering and organising by Marie Kondo. Good luck 😀👍