There are many style guides and rules for the use of commas but I am going to give an informal tip here.
Commas denote pauses in sentences. Some people use hardly any, others use them liberally. To figure out a happy medium, read your piece aloud with a pause at each comma. If you run out of breath then you need more commas or shorter sentences. If it sounds choppy or staccato then take out commas until the sentence sounds natural and you can’t feel the grammar.
