I'm still in the same boat as well to be honest, but I recently came across https://refactoringui.com/ on HN, which looks like it could be a really helpful resource for people like us. Still trying to get it expensed on my employer's learning budget, so haven't read the whole thing, but the excerpts I've seen so far have me looking forward to it.
Where most of us developers struggle with is making beautiful websites vs just something that works but looks ok.
One of the reasons bootstrap is so successful is that it's easy to use/integrate and produces a website that is very pleasant to look at.