My first simple tip: always save your work before testing
I wish someone had told me this when I started. You write some code, you feel brave, you click run or refresh the page, and then everything breaks. And you have no way to go back because you never saved a copy before testing. It happened to me twice with my first HTML page and I had to start from scratch both times. So now I just do this: before I try anything new in my code, I copy the whole file and paste it into a new folder called backup. Or I just press Ctrl+S a lot. If you are on your phone like I sometimes am, you can copy the text into your notes app first. It takes two seconds but it saves you from crying over lost work. Now I even do the same thing when I am customizing my M-Pesa statement template for my side hustle. Small habit but it makes a big difference. Asanteni for reading my small tip.