What are some of the most obvious signs of a baby's growth spurt?

The most obvious would be keep wanting to drink milk despite already ded him/her. Especially if u r breastfeeding, u will feel fhat milk is nvr enough. Like for mine, he usually drinks every 2hrs maximum but during this period, he wants milk almost every hour.

I read that babies going through a growth spurt will sleep more than usual. Apparently, there are important physiological changes that happen during sleep that are essential for baby's growth.

Most obvious would be feeding on demand and can go up to an hour or so. Else, for mine would have changes in sleeping pattern. Shorter naps, cranky.