Colour is so important. It’s not a case of needing to use the same shade the whole way through, but you absolutely need to consider the entire palette otherwise the connected spaces end up look disparate. You can use subtly different colours or ones that are a complete contrast, so long as they’re tonal and are planned together as a whole scheme.
The flooring is also a key part of designing one living space. Using continuous planks of timber is what I suggest most of all, because it’s practical and warming so makes sense for living and relaxing. Layer rugs throughout to soften things and to help the kitchen feel more in-tune with the living area.
And remember, the positioning of the furniture is just as important as the choosing. Consider a dining or kitchen table – they always look at their best when placed near a window or doors onto the garden and when you’ve thought about lighting the surrounding area with a few table lamps and perhaps a single floor lamp. It’s common to put a pendant light over it, but this will limit you because it means your table has to remain in that position, and if you have pendants over your island, they’ll compete for attention. If you want a soft seating section, that can happily go at the opposite end where a view onto the garden isn’t quite as necessary. There are no hard and fast rules, but these might help you with prioritising your space.