Semicolons don't get used very often. I think that people are weary of using them incorrectly or not sure about what they're for. So I'm going to try and add a little clarity.
The purpose of a semicolon is to seperate two independent clauses. Then they can live together in harmony instead of being broken up by filler words such as but, or, and, ect.
For example "The host was good last night; she had on an awesome outfit." Ok so both ends of this statment is independent all on it's own and when said aloud the sentence flows smoothly. Whereas If I were to say it aloud once again with a period inbetween it would sound like this, "The host was good last night. *breath in* She had on an awesome outfit." So as shown here the semicolon is good friend to flowing speech. It took out the pause and didn't call for over used filler words (conjunctions).
Don't use semicolons with conjunctions. Conjunctions are those filler words I touched on such as but, and, or, for, ect. A semicolon takes there places if the two parts of the sentence can be independant, meaning they can be split into two sentences that would do just fine on there own.
A good question to ask is why would anyone connect two sentences if they are already independant. The answer to this is that semicolons can help form things that connect together, adding to flow of writing. If one complements the other throw it in there and divide it with a semicolon, great!
I hope that this helped anyone out there; if I can clarify anything further let me know!