Start with obvious exits
Broken, expired where applicable, or unusable items are easier decisions than sentimental possessions.
Compare duplicates
Keep the items that fit current needs and avoid storing several backups without a reason.
Give undecided items a deadline
A temporary review box can prevent one difficult category from stopping the whole project.
Use appropriate disposal paths
Donation, recycling and hazardous/special waste rules vary locally.
General household information only. Follow product labels and manufacturer instructions. Electrical, gas, structural, hazardous-material and other safety-critical work belongs to appropriately qualified professionals.