Be what you would seem to be - or, if you'd like it put more simply - never imagine yourself not to be otherwise than what it might appear to others that what you were or might have been was not otherwise than what you had been would have appeared to them to be otherwise.
You know," he (Tweedledee) added very gravely, "it's one of the most serious things that can possibly happen to one in a battle--to get one's head cut off." pg. 199
'Have some wine,' the March Hare said in an encouraging tone. Alice looked around the table, but there was nothing on it but tea. 'I don't see any wine,' she remarked. 'There isn't any,' said the March Hare.
I'll try if I know all the things I used to know. Let me see: four times five is twelve, and four times six is thirteen, and four times seven is - oh dear! I shall never get to twenty at that rate!
I wish I hadn't cried so much!” said Alice, as she swam about, trying to find her way out. I shall be punished for it now, I suppose, by being drowned in my own tears !