These two are cliched verbs in Spanish, which means everyone talks about them. In simple terms SER and ESTAR are TO BE verbs, which means we have 12 different forms for IS, ARE and AM in Spanish.
SER denotes a permanent existence or reality and ESTAR temporary. But there is nothing permanent, or something can denote permanent for someone and temporary for someone. For instance, marriage, friendship, location, identity etc. But no need to get confused here, just follow the game of the rules as per the Spanish grammar and jump on the turf. You can not fight back and change the rules.
Anyways, the acronyms DOCTOR for SER and SPACE for ESTAR help a lot in memorizing the uses of these two verbs. DOCTOR stands for Description, Occupation, Characteristics, Time, Origin and Relation, whereas SPACE stands for Situation, Position, Action, Condition and Emotion. Remember that if you look closely DOCTOR has relatively a longer sense of being than the SPACE. For instance, “He is confused” can be both, temporary because of a situation (ESTAR), or it can be a permanent characteristic of someone. So, if you choose SER it will mean different and if you use ESTAR it will be different. Él está confundido (He is a confused person), Él está confundido (He looks confused). Ella está guapa (She looks beautiful {thanks to makeup}), Ella es guapa (She is beautiful {naturally}).