First of all, i just want to state that these are really great; I wish i had known about them earlier.
It would be great if you could also add some overall tips on the usage of semicolons as well.
Yes, this is the correct usage of a semicolon.
There are many great websites that can give you some good tips on how to use semicolons. Here are two common usages of the semicolon provided by the Writing Center at the University of Wisconsin-Madison.
Link two independent clauses to connect closely related ideas
This is what you have done in your example. You can link two complete sentences that are related using a semicolon if you want to emphasize that they are connected.
Some people write with a word processor; others write with a pen or pencil.
Link lists where the items contain commas to avoid confusion between list items
It can often be difficult to create a list inside a sentence, so a semicolon can help to break up the sentence and make sure your ideas are easily understood. Two examples they provide of this are:
There are basically two ways to write: with a pen or pencil, which is inexpensive and easily accessible; or by computer and printer, which is more expensive but quick and neat.
I like cows: they give us milk, which tastes good; they give us beef, which also tastes good; and they give us leather, which is used for shoes and coats.
Another helpful tip they provide is on when to use a common vs. a semicolon. If you are connecting two independent clauses and you do NOT have a coordinating conjunction, you need a semicolon. If there is a coordinating conjunction, you need a comma. (Coordinating conjunctions: and, but, or, nor, so, yet...)
The cow is brown; it is also old.
The cow is brown, and it is also old.
Be careful, 'however' is not a coordinating conjunction. Many people incorrectly use a common before however.
Incorrect: I like cows, however, I hate the way they smell.
Correct: I like cows; however, I hate the way they smell.
In addition, if one of the clauses is not independent, you must use a common.
Because cows smell, they offend me.