Buy a packing tape dispenser and plenty of rolls of tape, a few sharpies, and some sheets of "'fragile" stickers now from
Amazon or similar.
Declutter now and get rid of broken items to bin, things that are fine but you don't/wont use to charity shops (e.g. the freebie serving dishes you never use) etc. Including outgrown clothes and any duplicate items in kitchen etc. Go through clutter drawers, boxes of cables, kitchen cupboards.
Start packing, aiming for a couple of boxes a week, immediately. Starting with the heirlooms that you love but don't use frequently, books and media (dvds/videos, cds, etc). As you move into spring and do your annual changeover of clothes, pack the winter things. Pack away to good tablecloths and napkins, Bedding for spare beds, guest towels, and reduce everyday towel/bedding down to max of 3 per room/bed until you move (wash,in use, and 1 spare if needed).
Don't overpack any box but make sure they are full so they don't crush under weight above them.
Mark EACH box with the room it should go to, which side is top, if it contains fragile items. I had a master list which was numbered, and had the contents (roughly) of each box, and numbered each box accordingly. When I moved house and had time, I did a foolscap sheet with the exact contents of each which sat in the top of each box as it was sealed (saved a LOT of rooting when we arrived as I could open, see what I needed wasn't in it and just close over the lid again until I was ready to deal with it - but find things I was looking for).
Keep every bit of packing type material you get now to reuse - bubble wrap, foam peanuts etc. Newspapers are very useful to wrap around and scrunchie up to fill space (sometimes print can transfer so anything delicate, wrap in a sheet of plain tissue paper first, then newspaper).
Consider buying a bulk pack of moving boxes as they will stack better, but you could also ask local supermakets for boxes.
I found plates survived better stacked on their sides but wrapped in sets of 2/3 only and with a sheet or 2 of tissue paper between each and also surrounding them all to hold them
Together securely.
Towels can be used to wrap things like lamps or big decorative things.
Don't make any box too heavy. Use smaller boxes for heavy things like crockery and books.
If you have them, use vacuum bags for textiles (sheets, towels, clothes but also duvets, cushions, pillows etc). Real space saver to reduce the number of trips you need to make in and out and possibly reduces the number of physical trips with van.
If you plan to bring any fixtures and fittings, or plants from the garden, replace them
With functional versions in old house. So the fancy toilet roll holder can come with you but put something similar but cheap in its place. And tell buyers you will be taking plants, dig them
Out now before the growing season starts again and put them in decent sized pots to transport them and keep them
Until you have time to replant.
Make up 1 box that should move early on moving day - with mugs, kettle, instant coffee and teabags, sugar, biscuits etc. Paper plates and kitchen towel. Glasses or couple of packs of paper/plastic glasses, squash, maybe even some
Fizzy drinks - but be able to give thirst quenching liquids and snacks for all who are helping. Cleaning ispreay and cloths and gloves, loo roll for each bathroom. A few tees towels and a hand towel. A screwdriver, Stanley knife, no bags. The kit you need in the new house to make the job easier basically.
And also have a suitcase or easily identifiable box with a set of sheets for each bed, couple of towels, 1 change of clothes for everyone. So there's no rush to find anything else but someone can quickly make up beds and you have something to wear. (Sheets and duvet could be swopped for sleeping bags for night 1 if you already have those - or at least know where those are in case if gets late and you are too wrecked to make up beds).
Plan on moving night involving takeaway for dinner.