1. Take your time
It will take time to clear all of your junk as it probably includes at least a year's worth of miscellaneous purchases, unwanted gifts, concert tickets, receipts and one-off party costumes. Give yourself time to go through the things that are stashed away in your home, and don’t be scared to throw them away.
The rule is: if you have not used a certain thing for some time (let's say six months) and it has no sentimental value, it is highly unlikely that you will use it again. Tidy one corner at a time to make the task less stressful.