There are three major uses for semicolons. Note that an "independent clause" means a group of words capable of being a sentence by themselves.
Don't overuse semicolons. Instead, try to use them only when a clear and close relationship exists between the things you connect. In other cases, you might want to use an effective transition.
1) Between independent clauses of equal rank when there is not a coordinating conjunction:
2) Between independent clauses of equal rank when there is a conjunctive adverb or a transitional phrase. Note that the semicolon comes before the conjunctive adverb or transitional phrase, and a comma follows the conjunctive adverb or transitional phrase:
Conjunctive adverbs include: also, anyway, besides, finally, however, meanwhile, otherwise, therefore, etc.
Transitional phrases include: after all, as a result, for example, in conclusion, in other words, etc. You may wish to consult our materials on transitional phrases.
3) Between items in a list with internal punctuation in order to make the groupings within the list clearer: