“My long-term goal is to open my own restaurant.”
You are talking to a person you just met at a party. You say this while telling him about your job and your career goals.
My long-term goal is to open my own restaurant.
A "long-term" goal is a goal that someone plans to achieve several years in the future. Usually we think of a long-term goal as something that will happen in about 2-15 years.
Here's an example:
Do you have a specific long-term goal that you're working toward?
Of course, you can also talk about a "short-term goal", which is something you want to accomplish in a few weeks or in a year or two.
When you describe someone's goals, you say that their "goal is to ___":
My goal is to have it finished by the end of July.
Our goal is to improve sales by 10% this quarter.
You can also use similar words like "dream" or "plan" in the same way:
His lifelong dream was to become a writer.
My plan is to get into law school and study Environmental Law.
Use the word "open" to describe starting a store or restaurant:
Did you see that they opened a new Apple store near Lincoln Center?
Talk about something that belongs to you alone (meaning that you don't share it with anyone) with the phrase "my own ___":
I own my own home, I've got a steady job, and I don't have any debt.
You can also talk about "your own ___":
Running your own business is incredibly hard.