How to concentrate more on the time of deep work?

Plan clear objectives. Think how good You are going to feel when You achieve the goal. Write thoughts that interrupt work to deal with them later.

I use my deep focus time to charge my phone (on silent) so I don’t hear it. I make sure to use the bathroom before I begin and I have a drink nearby. I also make sure I’m in comfortable clothing so I don’t feel the need to fidget or change my position so much.