[mcdramamean]

Start with Bootstrap. Build as many sites as you can just using Bootstrap and then study what the classes are actually doing. Then replicate the classes and make changes to them. Bootstrap has enough that if you go through each thing it has, you will have a decent appreciation for the look and how the CSS/HTML/JS fits together to make a site. Then start using jQuery heavily. Find jQuery modules and use them. Play with the options. Then start playing with the code. Those 2 things will be good enough to then move on to something more complicated; which ultimately is just abstracting these basics and attempt to make them easier. But you have to already know what is happening if you don't want to get confused as to why you are using the tool and what your other options are besides this tool.