This is not easy to do. When you get arrested you are probably very upset and want to yell. You need to control your emotions and need to be polite. The police officers will write down everything you say. If you are being a problem for the police the DA is less likely to give you a break. So be as polite as you can.
You don't want to say anything that might hurt your criminal case. Anything you say can be used against you in court so be careful. You might think that you are helping your case, but the reality is what you say will not help and only hurt.
Ask for a lawyer
You have a right to an attorney, use it. It is important that you have an attorney there protecting your rights. Even if you waive your right to an attorney by signing a waiver you can still ask for an attorney later on. There is no reason to not have an attorney present. So protect yourself and ask for an attorney.