Tiling layout is always a compromise but, overall, the impact of walking into the room will look better if you have a near full tile next to the floor & cut the tiles around the bath & ceiling to suit, unless you end up with thin tile slivers; this will also help you maintain a 2mm gap around the bath which is essential for a good silicone seal. Similarly, whilst tiling from the centre of a wall outwards is standard practice, you can do this either on a full or half tile so you need to decide which will look better in the corners. Windows & other stuff can throw this theory off course & you need to compromise to get something that looks right as you walk into the room. Generally, tile slivers less than ¼ tile will look crap especially if the adjacent wall isn’t similar.
If you’re tiling floor to ceiling, your best is to start half way up the wall (or from the bath) & tile up & down as this will minimise the effect of tolerance & error as you tile. Start at the floor & you can be a long way out by the time you get 2/3 of the way up the wall; for this reason, it’s very important that your battens are absolutely straight, I use aluminum extrusion not timber.