Writing is much easier in silence. But writing happens in the real world. Silence doesn’t always happen. How do you deal with it?
First, make use of the time that you have. Even if it’s in the shower, plan your plot and develop your characters. That way when you do have time to write, even if it’s noisy you have a direction to take your writing.
Second, don’t focus on the noise. Right now I am sitting in a room with a loud clock. If I don’t think about the ticking, it doesn’t bother me. If I concentrate on it, the constant click, click, click is all I can hear. It’s enough to drive me mad. (Granted, some sounds you shouldn’t tune out, but for other ones, focus on not paying attention to them).
Third, plan for noise. Sure, in complete silence, you could sit and write dozens of pages a day. But absolute, quiet rarely happens. Set your goals knowing there will be interruptions and moments when all you can focus on is the ticking of the clock. Plan for them. Expect them.