1. I recommend reading through [1]; it covers pretty much everything you will need. As for websites, I enjoy
https://monkeytype.com/ because of how customizable it is. However if you're learning, I would recommend
https://www.typingclub.com/ until you no longer need to look at the keyboard. This shouldn't take too long, you don't need to do all the modules. After that, you can pretty much ditch typingclub and focus on [monkeytype|typeracer|10fastfingers] for your practice.
2. Focus on accuracy always. Speed will come in time.
3. If you want to quickly improve your coding speed, turn on autocomplete. I know some people bind certain symbols to snippets/templates (eg. "par"/"rap" expands to "(" and ")"), but I think this is a little too much. I would recommend training on passages that have punctuation and special characters, but after a certain speed, typing symbols and numbers isn't that tight of a bottleneck unless that's all you're doing. You will get used to typing them with more practice anyway.
[1] https://docs.google.com/document/d/1L-P68VDSGlpLM5A9tfRvWFoh...
