1. should probably turn on auto-save (diff people prefer different things) but it's cmd+shift+p, type "auto save" and select "toggle auto save" so vscode automatically saves after a short delay when you stop typing. otherwise you just have to go cmd+s each time you finish editing a file. some people don't like this though, because it can mask syntax errors temporarily if ur dev server crashes every keystroke.
2. sometimes the code is correct but there are squiggles. just cmd+shift+p and type in typescript: restart ts server. or idk i just quit vscode and open it again and then it's fine. this happens because of a stale ttsserver cache where it's in a confused state after u edit many files.
3. multicursor editing for when you're making n identical edits in n places simultaneously: good shortcuts are (cmd+shift+l, to highlight the n appearance of the thing) and (holding option and clicking every place you want to start adding something, then doing cmd+right arrow and typing what you want at the end. for example, putting several phrases into a list).
4. other multicursor trick. select the n thing you want to edit, press cmd+d the number of times it appears next / number of times you want that n thing to change type your change, and for example if you're closing it (same list items example) you can go to the closing item you want to replace, click cmd+D the n amount of times you want to replace the n thing, and type the replacement edit.