In a PhD (or academia in general), there's always pressure to perform. To get the results, to write them up and get them published.
But by putting too much pressure on results in the short term, it's easy to neglect the need for practice; the need to work on skills without worrying too much about the end product.
Let's use a sports analogy. If you spend all your time in competitive matches, you might develop a certain toughness; an ability to keep on grinding away, but without actually getting better. You'll have some wins, but you'll never reach the top.
Under the pressure of performance, you can't experiment and adapt. You can't work on basic technique when you have to react right now; your performance will stay at the level you can already perform instinctively.
It's in the times between matches, away from the pressure of performance that you can work on skills. In sports there is a clear separation between practice and performance, but in PhD work, where you have to arrange your own work in a way that's conducive to developing your research skills, you have to create that separation.
Take some time out and work on the basics. It will pay off in the long run.