Managing thoughts while facing the WHOLE house

This is a two-part question:

Part 1:
So for the week 1 organization assignment, I chose my dresser instead of a closet. My dresser had overstuffed drawers and includes a cubby I’ve shoved things in for years. I felt great about it! Took bags of stuff to donate and threw a ton away.

Then I looked around and everything else looked so cluttered, both in our bedroom and in the rest of the house.

How do you recommend managing thoughts when facing a HUGE organizing project – like a whole house?

C – clutter in every room
T – I’ll never get it all organized (or my family will just clutter it again)
F – overwhelm
A – procrastination ./ avoidance
R – clutter in every room!

Part 2: I am someone who really enjoys purging; cleaning out certain areas (my closet, the kitchen) is something I do fairly regularly. But my husband and both of my children really want to hang on to EVERYTHING. I don’t want to have a “manual” for how they should be, but how do you recommend organizing around people you live with whose stuff fills up the common areas? (And part 2a: how do you teach kids that it’s okay to part with things? Mine are 10 and 12.)

Thanks for your suggestions for bridge thoughts while I take it one closet at a time!