This
Sometimes you just gotta physically stop yourself from checking XD For a while, I made it a rule to not check back on my updates within 24 hours of posting it, and now I've let go of that rule but I find I'm not slipping back into my old habits and genuinely don't have the strong, persistent urge anymore 
Another thing I do is to keep a buffer, so the update I post is not the update I just finished working on. Since my urge for validation is strongest with the thing I just finished, it helps me to have a system that makes it impossible to show people the thing I just finished, which gives me a healthy amount of 'psychological distance' XD
Finally,
In practice this means only working on my comic when I have a burning urge to, or when I'm bored and have nothing better to do. This may not work for everyone (e.g. if you're planning to go pro), but it certainly helps me not-crave as much validation because the lack of validation doesn't make what I did a waste of time :]
(This is basically just 'do your comic because you want to and because you enjoy it first and foremost', but taken to its logical extreme from the perspective skeptical to the idea that you can conjure 'enjoyment of working on your comic' at will :P)
And yes, it's human to want validation; don't let anyone shame you for it! Only try to curb your craving for validation if it's actually interfering with your life, not because you feel bad about being an 'attention-seeker' or smth XD