I have question concerning salah please.

If for example during my salah , I think about something bad , without do it intentionally makes my salah baatil?

For example, I prayed, and one music just come to my mind and I tried to directly ignore it and change my mind to be more concentrated and continued my prayer.
Is it ok? Or I have to repeat my namaz again?

Do you have some advice to be more concentrated during prayer please?

Your salat is not batil since is thinking. You don’t have to repeat your salat.
However, it’s important to reduce the thinking:

Few advises:

1. Prepare for salat in advance. Meaning, make wudhu some minutes before the actual salat time. Do some optional payers before or do some long prostration before the actual obligatory salat.

2. Try to spend time to understand whatever you recite in salat.