i would say the tailwind docs themselves and looking at the examples were a big help. for instance, the way they visualize their flex elements was enlightening. also, learning about how atomic css is a useful paradigm was the biggest motivator for writing more meaningful and expressive css. i'll list some things i've bookmarked:
and finally, it's always useful to read critiques. the following article is well written, in my opinion: https://www.browserlondon.com/blog/2019/06/10/functional-css.... through that i learned that tailwind has a useful feature: @apply, which you can use in conjunction with a standard css class approach. i.e
container {
@apply color-grey-100;
box-sizing: border-box;
}