While I agree with all of that, @Paul_Wilkins, you haven’t mentioned the most important step. That’s probably because it comes so naturally to most of us that we don’t even think of it as a step, but I suspect asasass has never been introduced to the idea, as he seems to skip this stage.
The very first step is planning. I don’t mean getting an idea and immediately flinging code at it. I mean sitting down and thinking about the project. What is it for? What content does it require? How should it look? How should it behave? Think through the entire project carefully. Don’t just think about one single aspect, but about the page / project as a whole. How do the parts relate to each other? Does the behaviour of one affect the behaviour of another?
In the real world, doing the first thing which occurs to you without considering the consequences is seldom a good idea. “My shoes keep falling off. I know! I’ll superglue them to my feet!” For all I know, that might work brilliantly - but you’re likely to regret the decision when you want to take them off again. Tying your laces would have been a simpler solution. As with life, so with code: simpler is often better.
Once you have a clear idea of the finished project, then you can start with the content and add the HTML markup, then progress to the CSS and finally the JS.