Practice in Sections and Practice with Distractions.

Once you have outlined your speech, presentation, or video, you will need to practice to ensure a professional presentation.
Most speakers will run through their speech from the beginning until they hit a snag. Then regardless of where they were, they start the next practice run right back at the opening sentences. 
This isn’t effective or efficient; it simply makes you an expert in delivering the first portion of your talk.
Go back to your bullet point notecards and number them clearly. (This material may change as you refine your presentation.) Resume practicing, but this time, when you hit a problem (forgotten material, stumbles, etc.), stop, regroup and then restart—but only from the previous notecard. Do not go back to the beginning!
If you have set aside plenty of time to practice, try jumping into your speech at different points. This will ensure you never lose your way on the day.

Too many speakers practice in a perfectly quiet setting. But speeches and business presentations are rarely given in silent rooms. 
When you practice, allow small distractions to be part of your space. You will be far better prepared for the real-life setting in which you will speak.