Wedding day is indeed the most important day of your life.
It is crucial that everything is at the right place and everyone knows what to do.
The self made bride who does not want to use any wedding planning service should know that planning well is 90% of the job. The rest is luck.
In order to reduce your risk I suggest you use the following template. You can print it on a large paper and post it to your wall. It will help to scheme things out and sort them in packages of activities.
It is a Work Breakdown Structure. I invite you to read more on WBS so you could think of assigning tasks and give them a chronological value.
Download the wedding-work-breakdown-structure.pdf