Nursing diagnosis involves making a clinical judgment about a patient's health issues and developing a care plan accordingly. It has three main parts - the problem, likely cause, and defining characteristics. Common types of nursing diagnoses include actual, risk, and wellness diagnoses. Accurate nursing diagnoses are important for effective patient care, developing nursing autonomy, and ensuring accountability. However, errors can occur if the nurse lacks knowledge, misinterprets data, or chooses the wrong diagnostic label. To improve, nurses should seek guidance when unsure and state diagnoses specifically to guide interventions.