A stiff drink...… sorry, I couldn't resist.
Marie....I start with windows, inside and out.
Depending on where you live, you might want to start on the closets and drawers in the bedrooms. Now is the time to really start the decluttering process. Which will be easier each year. These are the places most people don't go into with much effort.
Donate what is useable, clean and in good condition; even if you don't think someone would want or use it. People like different things. Be sure to save your receipt for next years taxes. I always write them down and then go to Word in my computer and type everthing up and each page is added up with a total on the last page. Here you staple your receipt from the donation center for your taxes. Our guy just loves it all totaled and everything. Google the value on donated irems for a place to check on how much you can use for each donated item. You'd really be surprised at what you can write off.
Also as you are stripping out those closets, check and see if they need a new paint job or a few new brackets, baskets and so on for storing your goodies in or on. I found the perfect bracket online at Wayfair to attach to the wall for either my pants or tops. They fold either right or left and so they pretty much collapse back onto the wall! They have 5 or 6 metal arms to hang your thing from. They were only $7.00 each too.
I just know once you finish those, you'll head for the bathroom and then the kitchen to clean out cabinets and drawers there too! Good luck Marie. I started last year with my cleaning and decluttering process and donating to Purple Heart. They are a great charity to doate to because they donate just about 100% of their profits to our Veterans!
I would say decluttering first. Get rid of things you no longer need or want. Then you can clean what you keep.