Look at who is sharing the information. If it's from friends or family members, don't trust the posts unless they are personally on the ground or a confirmed expert.
Trust the professionals. Legitimate mainstream news organizations are built to vet these things for you, and often do report on the same videos or photos taken by real people after they've confirmed their origin.
Keep an eye out for content warnings on social media sites for individual posts, which can appear as labels below links or as warnings before you post something that could be misleading.
HOW TO SPOT A FAKE VIDEO:
See if the video is being posted by multiple verified news outlets. Check the description of what happens on screen against reliable sources.
Look for notable signs like blurriness in the foreground or background, pixelation, changes in color, or slower or quicker movements that don't match normal human behavior.
Listen for edited audio, including cutoff speech, sound that's warped or modulated and speech that sounds slower or faster.
HOW TO FIND THE ORIGINAL VIDEO:
Run a clear and identifiable screenshot of the video through reverse image search tools like Google and Bing to find other instances of the video posted online. Also look for logos, credit or handles on the footage to find the original source.