At the base line, social media is a good way to connect with agents.
Agents talk about their manuscript wish list (#MSWL) from time to time. They list what they’re looking for in the next book they represent. Look out for them. You might see one that matches your book.
However, warning: do not directly contact an agent over social media. Social media, whether it be Twitter or Facebook, is not their work. They’re not on the clock. It’s their time to be themselves. So, unless asked to, don’t query them through Twitter.
The exception for this rule? Twitter pitch contests.
During the contests, writers tweet their book pitch using a particular hashtag. Some days are only for romance books, others for YA, etc. Fellow authors will retweet your pitch to help you reach more agents, but they are not allowed to “like” it. Only agents will “like” the tweet to show their interest in your work. Then, you can reach out to those agents.
When do these contests happen? Well, I got a deal for you. I have a list of the twitter pitch contests for 2020 right here. Mark those days down if you want to participate.
I hope this helps!