Your goal is to capture at least 100 clips per hour.
There is never too much content, so just capture everything you see. Make sure you are taking both pictures and videos.
Keep in mind to film clips for transitions! You can add a swipe up/down or left/right movement to stitch together (like this), and you can cover the frame for a reveal (like this). Get creative with it.
ALWAYS shoot vertically when filming. You can switch to landscape for photos.
Use the wide-angle mode when needed. Since you are shooting vertically, it will be tricky at times to fit everything in frame.
Only use “portrait mode” for photos when you are in daylight and you are close to your subject. It looks pretty blotchy and unprofessional in photos that are shot indoors with overhead lighting.
Shoot in 60 fps so that you can put clips in slow motion without them looking blurry/choppy
Make sure you are not blocking the sight of view for any guests. Most of your day will be spent crouched/low to the ground so that you are not disturbing the wedding for any guests or getting in any of the photographer's/videographer's shots.
Throughout the day, be sure to “favorite” the best clips that you know you want to edit with. This will make them a lot easier to find later on after you have thousands of photos/videos to capture.
Try to mic up the groom for the first look and ceremony if you can. If you find yourself unable to mic up anyone for moments like ceremony/reception, lay the microphone near the audio speaker.