The way we blink isn’t usually noticeable to others, and isn’t usually a factor in communication, but we do have a tendency to blink more and rub our eyes when we’re tired.
So here is a tip: If you can, avoid rubbing your eyes, or rub them out of necessity rather than habit, as you don’t want to come across tired when communicating with others, and it will make you disengaged and possibly look a bit disinterested.
Now, a word about blinking and lying. Many have said that if someone blinks when telling you something a bit suspect, they’re lying. That’s not true; people blink all the time and aren’t usually even conscious of it. I bet you are, now that you’re reading this! Anyway, counter to this idea is the fact that many people do believe that blinking equates to lying, and will deliberately not blink whilst telling a porkie. If someone looks like they’re straining not to blink, it doesn’t necessarily mean they’re lying, but something maybe wrong.
Eye rubbing, other than being an indicator of tiredness, can suggest lying or discomfort, especially if the gaze shifts away whilst the eye is rubbed. The thing to remember with all of this, is you need a baseline; some people just blink a lot.