Will the judge believe you or cops?

I'm only in high school, but I've been taking training courses to be an attorney since middle school. So, I would take my own advice.

Typically, in most criminal cases, when it comes down to "he says, she says" the judge will usually believe the police. This is how police brutality and violations of Miranda rights can be so blatantly ignored. If the trial is allowed to continue, and the prosecution has a solid case, the judge may take the Word of the police officers, or forged witnesses, and proceed to hand down a guilty verdict.

However, if you believe that an injustice is being done, and the only evidence against you is testimony, you can often call the police out, and rattle the prosecution's case by pointing out that testimony alone is not enough, material evidence is needed. Also, ask for another police witness if necessary, perhaps you can find a discrepancy between their testimonies. If testimony is the only incriminating evidence, and no (or not very influential) material evidence is uncovered, a not guilty verdict will most likely be passed.

However, if there is substantial material evidence AND police testimony against you, you might as well get chummy with the prison guards, because chances are you'll be put away, whether you're innocent or not.

Hope that helped. Police are sworn law enforcement officials known by the court and trained on how to testify--you are not. Testimony is "direct evidence" and is all that's needed for a conviction.