What is the best way to start decluttering when the whole house feels overwhelming?

Keep a donation box near the door. When you notice something you do not use, drop it in. Decluttering got easier when it became ongoing instead of one giant project.

Do a trash pass first. Throw away obvious garbage, broken items and expired stuff. It reduces the volume before emotional decisions begin.

Start with one surface, not one room. A kitchen counter or bedside table gives you a visible win. Momentum matters more than perfection.