Hi there. If the tile you have has character, you could pull a colour from some of that character, for example if the tile had a beige fleck through out you could use a similar beige tile in the bedroom, otherwise just choose something that compliments the tile well to create a soft transition. Then use the colour of the existing tile in the room somewhere, with your bed linen for example or bedside lamp. Feel free to share an image of the existing tile.

Used beveled subway tiles for whole bathroom without thinking about internal corners so the corner looked terrible then the silicon went on and it still looks terrible I guess apart from an aluminium strip or a marker to go across the silicon there aren’t many options

Eh ? You want white or off-white or similar ? Your kitchen is white and off-white , with quite a light wood . And a nice red toaster . I have noticed the toaster , and commented on it . You have purchased the toaster . Other people will notice the toaster , and comment on it . Because it is the only mildly interesting thing in the kitchen . Dark grey doesn't sound interesting , but charcoal does , so I am hoping it is closer to charcoal than dark grey . Am I overly optimistic ? Can you swap the dark grey for black gloss , because I suspect black gloss subways would look quite good there , and tie in the oven and cooktop too . Now what would happen if you were stuck with the grey or charcoal , and went out and bought a dozen crisp white subways , and a dozen Red subways . Get your 30 or so charcoal subways , and lay them out in a rectangle on the floor . Take 6 out in a reasonably random way , and put white ones there . Then take out another 6 , and put red ones there . Depending on the grey/charcoal , it may look crap , or it may look okay . If it looks okay , put the dozen grey ones on the top , take a few more away , add more red and white . Overdone ? Underdone ? Have a play . Don't like it ? Get all the grey ones , and 'stand them up' ( lay them vertically ) . Lay a line of red ones horizontally across the top , another line of white ones horizontally across middle . Swap them . Don't like any of them ? Get some brownish Tavertine Tiles , or an Orange ( or red or yellow or citrus green or your favourite colour ) glass splashback . Experiment . Put the on the bench and imagine . Thats what I'd do anyway . But I wouldn't do only dark grey , and I probably wouldn't do charcoal on its own , but I'd see first .

This is the only photo. Wall colour is white and joinery is black. The floor tile is the light colour and will be in the entry, kitchen, family and dinning areas as well as bathrooms laundry and toilet. Can I pull off the dark carpet or should I choose a lighter shade to compliment the tile?