We've all heard the old adage "write what you know". This could mean many things, such as writing on topics that you are familiar with, sticking with genres in which you excel, etc.
One way I like to interpret it is "give your characters the same problems you have". Many of us tend to write ourselves into our characters, giving them the same general flaws, weaknesses, strengths, and aptitudes that we have--or would like to have. We model our characters on ourselves in one way or another.
However, this could actually be a mistake in the long run.
Imagine if you read a dozen books written by the same author, all with characters that are somewhat similar to the author. This will likely mean that the dozen books will all have characters that share some similarities, and the books will be populated with supporting characters that are pretty much all the same.
Of course, this is painting with a pretty broad brush, but the point I'm trying to make is this: don't always make your characters like yourself.
It's hard to write characters with whom you have NOTHING in common. If you read over your current WIP, no doubt you'll see a character or two that you find little to identify with. As you read, you'll likely notice that your portrayal of these characters is weaker than the rest of your characters. This is because you have no way to get inside the mind of a person who has NOTHING in common with you.
However, becoming a skilled writer is about stretching your limits and pushing beyond what you think you can do. These "not-you" characters may be weak now, but eventually you will become adept at writing people with whom you have nothing in common.
They will be the characters that will not only make your work better, but they will help you to identify with the people in your life that are completely out of your scope of understanding. The more you write them, the more you will be able to put yourself in the minds of people that are nothing like you. It will not only make you a better writer, but a better, more easily relatable PERSON as well!