Integrated development environment

An IDE

I use vim and gvim, but Microsoft's Visual Studio Code is available for Windows, Linux and MacOS and is probably a better choice for most people. Using an IDE to edit your site makes things a lot easier. The code syntax is highlighted, as well as the row numbers, so you can easily get to the source of any problem without having to count.
IDEs will help you pick up where there is a missing closing tag both by highlighting the syntax and with error messages.
If you're already a programmer, you might already be using vim. I prefer it because I can easily record macros, cutting down time taken for time-consuming tasks, but it's not trivial to learn how to use it.