Sock accounts and their puppet master are not always logged in at the same time. While editing this factor is less useful but as sock accounts are the same person it would only be natural for them to edit in the same time period which can provide you a clue. On chat however, this can prove to be quite effective. Most of the times, when a sock puppeter decides he wishes to be on chat with another one of his accounts to achieve any of his goals, he must exit chat, log in on his sock account and then make a return with his new account.
My encounters with sock puppets, I have seen many who instead of adopting a good avatar, instead adopted one of the Avatars offered on the internet. More experienced sock puppets do choose different avatars, however even they can make a mistake, choosing an avatar that had some sort of connection to the avatar of their previous account.

Unfortunately, this isn’t really feasible, from what I understand. Do not share shit you don’t want other people to know, keep photos of yourself off the net if you don’t want to be identified. That’s basically it. Unfortunately the tech solutions nowadays just reduce the risk, they don’t eliminate it completely. Especially since it is very to hard to, for example, use Tor all the the time, or to never reference your real-world identity or anything about it, or to type in a way that copies JK Rowling instead of following your own patterns of typing and speech. So, the practical solution is, keep reading, keep learning, keep taking steps to lessen the risk of leaking all your information, keep taking steps to increase your privacy online.