If you're planning on having a successful phone interview with a hiring manager please make sure that you are in a quiet/private place.
Please make sure that your cell phone gets reception! You're aiming to carry on a productive call. Nothing kills that momentum more than static-y interference.
If there is a lot of background noise or the manager can only hear/understand every couple of words, the interview will probably not go well! In addition, you and the hiring manager probably don't want to get stuck playing phone-tag for 10 minutes until you find a reliable location.
Put yourself in the manager’s shoes. If that person has trouble hearing or understanding you, it’s going to make it difficult for them to get a good idea of your background. On top of that, you're unwittingly making a negative first impression by annoying/irritating them.
When you take a call in a crowded place, some hiring managers interpret that decision as "I didn't care to prioritize or prepare for [hiring manager's name]." That's clearly not what you intended but that's how it might be received. Here, you're starting your phone screen at a disadvantage. You'll have to work even harder to overcome your rocky start.
Make it easy for your counterpart to get you. That means anticipating and removing potential distractions. Put yourself in the best possible circumstances to succeed.
Read these resources to improve your interview prep: