How to use unless properly.
This must be a dumb question. How do you use this 'amazing' word unless.

Here's example sentences:

1. I'll fire you, unless you dance for me.
2. I wouldn't work here, unless I were pathetic.

Do you, native speakers' have some secret, magical formula to understanding where and how to use this word. My teacher said that it changes the main from positive to negative and visa versa, but this is difficult for me to understand....it changes the main verb from positive to nevative...

Question

How to use unless properly.
This must be a dumb question. How do you use this 'amazing' word unless.

Here's example sentences:

1. I'll fire you, unless you dance for me. 
2. I wouldn't work here, unless I were pathetic.

Do you, native speakers' have some secret, magical formula to understanding where and how to use this word. My teacher said that it changes the main from positive to negative and visa versa, but this is difficult for me to understand....it changes the main verb from positive to nevative...

Answer

Here's another way to look at it:
"I'll fire you, unless you dance for me." = "I'll fire you, if you don't dance with me."

"I wouldn't work here, unless I were pathetic." = "I wouldn't work here, if I weren't pathetic." = "If I worked here, I would be pathetic."

"I'll go for a walk, unless it rains." = "I'll go for a walk if it doesn't rain."

"Unless..." really means "if...not..."

Answer

When you use "unless" you're making conditions. The same is true when you use "if" but the verb does change from positive to negative (or vice versa). To change your example sentences to "if" sentences and keep the same meaning, they would be written like this:

I won't fire you if you dance for me.
I would work here if I were pathetic.

The nuance is a little different, but the meaning is substantially the same.

I hope that helps!

Answer

Here is the structure.. 
First you have to put the sentence which contains the action that will not happen if the action in the next sentence happen 
Then you put unless 
Then you put the action that the happening of it will stop the action in the first sentence.. 
e.g
You will pass the exam unless you waste your time