basic meditative practice every day for 10-15 minutes to learn how to simply slow down the random flow of thoughts enough to focus on one. don't expect to "empty your mind", which is a misinterpretation of eastern practices and generally BS anyway.
once you can hold a single thought for just a few moments, then add a simple distraction like water dripping or soft music. repeat your efforts to keep focused on the single thought until your mind learns to tune out that distraction.
after several days (or longer for some), you'll find that you can tune out almost any external distractions when you need to.