I'm 2 months from moving and am starting to make my action plan.
So far, I've been assigning myself small tasks to get done by the end of each week. Things like going through the kitchen cupboards and getting rid of expired stuff, sorting drawers out, sorting wardrobes for charity shop etc. If you have time, a little bit each week before the major packing starts will really help you get organised.
Spreadsheets and lists are the way forward. I realised this when I packed up my house for an international move and customs required a list on each box of the contents - unpacking was a dream!
My intention is to issue the removal people with a very crudely drawn plan of the house with rooms numbered, and all boxes have the number of their destination. Masking tape also works well as you can put it on furniture items and not cause damage when its removed, and can be written on. This way you can also add your room numbers to the furniture items so they go in the right place too.
This will go completely against everything I've just said about organisation, but we usually have a box that gets moved last labelled something like 'Crap from the kitchen side', because inevitably, this is the stuff you'll need most urgently and when you're in a panic because its gone, you'll have the conversation with everyone of 'where did you last see it?' 'on the kitchen side'. Has worked wonders in the past
Put your important documents like passports, birth certificates etc somewhere safe. Don't do what my parents did once and put the cardboard box of important documents in the same room as stuff to go to the tip.
Oh and put your iron in the same box as your kettle, because every time I've moved this has ended up missing and therefore when I need to go somewhere I can't find it 