How to make my handwriting better? neeeeeed help.?

I write very quickly and am usually pretty impatient when i write because i like getting the writing done. Because on that, my handwriting is very sloppy and embarring. I tense up when i write and hold the pencil very tightly when i write a lot. I see that a lot of my other friends have neat and clean writing or really pretty swoopy calligraphy like writing. If anybody has any tips or ticks on how to help me get my handwriting neater/cleaner it would be SO appreciated. thanx