I can scarcely believe it was five years ago, but I went into some detail about the day of a British infantryman here. There's a lot more that I'd add to that answer now, if I were to write it again, but it should give a good overview. There's also this one on British rations and food experience, though it covers a bit of the same ground (albeit in more detail).

Beyond that, Richard Holmes' magisterial work on this subject is Tommy: The British Soldier on the Western Front, 1914-1918. It's amazingly accessible and well-written, but is also the product of years of well-sourced research on the author's part.

I'm sorry that all of the above is so Anglo-centric, but that's what I work on.