Tips for Writing Your Own Wedding Vows
Agree a Style/Length - You vows should of course be unique to each of you, but it can be good in advance to agree on a rough length and style.
Read Lots of Examples - Search Pinterest for examples to give you a feel of the kind of wording that people include.
Make it Personal - Instead of writing about love in general, write about your love and the things that make your relationship unique.
Practice Out Loud - Practicing out loud helps you hear how the words sound, and will make you more confident on the day.