Civil rights are individual rights the state/government protects infringement by its own actors. For example the government protects your right to an education. If the state denied you an education then that would violate your civil right. There are exceptions to the rule. The state may infringe on the right in some cases if there is a compelling or substantial justification. This is complicated exceptions but apply in very rare cases such as public safety or another compelling societal/ policy need.
Determine the state actor
A right may be violated but it must be done under the color of law by someone using their authority as an officer,official,or authority to act by the state. If for example court clerk that works part time at a private business such as McDonald's retaliated against you by refusing you service there would not be a civil rights violation. If the police department or a public school retaliated against you for suing them, then they have violated your right of equal protection (class of one) if they acted with their authority as a police officer, board member, or employee of the school district, not a private individual.
If no state action determine if there is a private discrimination exception
There are some exceptions for private actors constituting state action. Sometimes if a private individual or entity is performing a government function or a function traditionally done by the government, this constitutes state action.
Also some types of private discrimination such as against a protected class (e.g. race, gender, disability, religion) are also actionable as civil rights violations. There are very few exceptions for private discrimination so the general rule is no civil rights violation.
Determine if they acted with malice or reckless indifference and violated a clearly established right
If it is determined that the person acted with malice or reckless indifference then you can sue them personally with limited exceptions.Some functions such as judges and prosecutors generally cannot be sued individually acting in that capacity but maybe if they do a function outside their duties which are immune as an officer, they can be sued. If they simply were negligent unless it was gross negligence or acted incompetently then they are either protected by qualified or absolute immunity.
If immunity applies then you cannot sue them individually just officially which requires the agency to be liable.
Determine if there is a policy or custom that contributed to the situation
The state will not be liable for an individual acting in their official capacity unless their was a policy, custom, or practice which contributed to the act of the state officer. If for example a police officer simply was enraged by a suspect and beat them without justification because he had a bad day when they were trained not to do it there would not be a policy that caused it.
A state agency is not liable for isolated bad acts by a rogue state actor.
If for example, the policy for that particular department that all violent complaints against officer were never addressed which allowed an officer to continue the behavior then that would constitute liability on the agency having that policy.
If there is a policy or custom then the agency may be liable for the conduct of the agent.
Determine if the agency is a local, state, or federal entity and what immunity exists
Even if there are policies, customs, or practices, that is itself not enough. State and federal government are protected by sovereign immunity. Cities and counties are not protected by the same immunity. There are certain waiver and abrogration depending on the facts and rights violated. If you can breach it with an exception such as the Americans with Disabilities Act (ADA) which congress waived a state's sovereign by accepting federal funds then the suit can proceed against the entity and the actors in their official capacity because the immunity does not apply.
Determine your administrative remedies.
Before a civil rights suit can be made, the individual must exhaust administrative remedies. For example, if someone was discriminated against in employment for being disabled then they could file a complaint with the Equal Employment Office Commission (EEOC). The EEOC would made an investigative finding in an attempt to settle the case or prosecute it. If they feel there is no case then they would allow the plaintiff to sue in court. The court won't take the case if the administrative remedies were not exhausted.
Determine the proper forum and remedies available
Once you determine your rights were violated, you need to determine if there is federal jurisdiction (which there usually is) and if you want to proceed in federal court. Federal courts generally award lower damages but much more likely to find for plaintiffs because of the types of cases.
State cases award higher but many times states are not very empathetic to civil rights claims.
Also some violations only provide for attorney fees while some allow recovery for damages. This depends on the basis for the claim and what is allowed.
File suit within the statute of limitation period
Civil rights cases usually apply the state personal injury statute of limitations such as in California it is two years. There are other statutes that specifically set the period but generally when not stated it is the state's personal injury statute.
You must file within that period unless it was tolled. I recommend filing in federal court.