Great tips, cheers.
This might sound like a weird one but I make sure I put shoes on. Something in my brain clicks as I often just wear socks or slippers round the house.
The 90 mins / 30 mins thing is interesting as well. I find I get distracted more easily at home but the periods where I'm working, I'm working far more intensely. I've observed that it averages out to broadly the same productivity, and so I no longer get worried that I've been distracted for a while (I can't do music though - makes me stare in to space while listening).