The most major difference between first-degree and second-degree murder is premeditation. First-degree murder willfully, deliberately, and premeditatively kills another person, while in second-degree murder, the killing was intentional but impulsive or unplanned.

Summary of the Difference The state of mind of the murderer is what predominantly distinguishes first-degree murder from the other categories: the murder was planned and executed after thorough consideration. The existence of a murder plan, that is, acquiring a weapon beforehand or lying in wait for the victim, are all strong indicators of premeditation, among others.
A person killed in anger is said to have committed second-degree murder. The killer had intended to either kill or inflict serious bodily harm, but the killing was done in the heat of the moment without any premeditation. Murder regulations, along with their classifications, can differ widely among states or jurisdictions. It is a must to consult an attorney for specific legal advice, as the subtleties of a case are very important in deciding the exact charge and possible defenses. The Louisiana State Legislature website (https://www.ambeaulaw.com/) gives information on the state's specific statutes.