Don't be tempted to decorate everything too quickly.
It's wise to live in the space for a while and see how it works for you before investing in big ticket items.
Related to the above don't overfill a space. A tape measure is your friend. It's also worth marking space out on the floor with low tack tape to see how furniture will really fit into a room and how the "flow" is around it.
Don't discount second hand furniture. Vintage furniture is often better made and less expensive than modern pieces. It's amazing what a tin of paint and new handles /upholstery can do to transform a table/chair/cupboard/chest of drawers etc and make what were initially very different pieces co-ordinate.
Try and form a style/theme for your home so decor flows from room to room. I dont mean everything has to be the same colour rather the "look" you want eg minimalist/modern/vintage bo-ho/lux etc
Take a room at a time having decided the above and complete it before moving on. It's better to have a few rooms "done" than every room painted but otherwise unfinished.
Make some key investments if you can afford to. As a pp has mentioned I still have the same pots/pans/knives for bought 20 years ago. They still look good and function beautifully.
On the other hand for everyday use I have pretty bog standard white plates and glassware. They inevitably get chipped/smashed through use. You can still make a table look beautiful with lovely napkins/flowers/candles etc even if your tableware is very simple.
Lastly think about storage. You will never have enough
. Having nowhere to put coats/shoes out of the way and cluttering a hallway will drive you potty (if you are like me).
Things like coffee tables with storage are good - as is any furniture that can be dual purposed.
Lastly don't paper over the cracks. You need to work from a good foundation. So don't put in a new bathroom if the plumbing/boiler etc are old. Your new shower won't feel wonderful if the water pressure is useless. Or a bedroom might look wonderful but is freezing because you didn't prioritise good insulation in the loft and double glazed windows.
Good luck and have fun!