At four many children still find managing their feelings difficult especially when they feel frustrated about something happening in their environment they may not have control over, they are seeking connection or if they are tired, hungry or over stimulated.
Many children need support in developing self regulation skills. Firstly identify tantrum triggers so you may plan ahead. Some children do not cope with sudden changes in plans so talk to your child about what will happen in advance.
Give children choices that will be a win/win for example ask a child to choose from two sets of clothes they can wear to an event. Be consistent in setting boundaries and expectations. Be sure to praise regularly.
Ensure to wait until the tantrum is over before you discuss the event with your child calmly. Let the child know you are there emotionally, label emotions, discuss some alternative ways of dealing with the situation and encourage the child to practice new skills. Developing these skills takes time so be patient and supportive.