How to build actually good roads and connections between areas?

I know this question is pretty vague but I find myself always struggling with traffic jams. I am really bad at road hierarchy. I use public transportation often, mainly metro but it still doesn't help. I also have a problem in highly populated areas with insane amount of pedestrians blocking intersections, I know there should be over or underground pedestran ways but I don't want to build it over every single one. And I try to plan ahead but most of the time it always ends the same. With me having to basically bulldoze whole areas just to change the roads. Traffic jams mainly occur in cargo transport areas and highrise areas. I'd really like to build nice and coherent cities but I really struggle with my actual skills. If needed I can send few screenshots of my current city.