I put my phone away so I can't see it/easily reach for it, put some lofi music in the background, and light a scented candle nearby (I have one that I light exclusively when focusing). I also make sure my bottle is full of fresh water, my desk is clean, I am comfortable (not cold/hot, hungry, thirsty, etc.), and my window is open so I have some fresh air from the nearby park (unless it's super cold outside). And then I get to work! I always have a to do list so I stay organised and know what exactly I want to achieve, and I make sure to drink water every once in a while. You can try any or all of these methods and see if they work for you – hope they do!