Buying too much storage
Leave the storage shopping trip until the end. Once you've decided what items you're keeping, then it's time to sit down and work out how much storage is actually required. Buying extra before you've finished, means you'll probably end up keeping more stuff than you need.
Don’t over commit
Setting aside a day to declutter your entire house is biting off more than you can chew: you will burn out. Set aside blocks of two or three hours and go from there, working your way through rooms or categories, like clothes and books.
Finish the job
Choose a room or task and see the job through from start to finish. Although it's tempting to leave that bag of clothes in the boot of your car for months, do yourself a favour and take it to the donation bin the same day.