The fact that you are aware of this is a great start as far as trying to change, if you are trying to change.
I had to learn to curb my tongue the hard way, getting my head bashed and some punches to the gut and neck for good measure. It worked, but I would not recommend this route. There are easier ways!
I guess just try to treat your friends and family (and strangers!) with the utmost respect and kindness. Try it, you might like it!
Good luck, and let us know how it goes!