Craft is one of those things that must be learned. Some people come to it faster and easier than others. Some people really struggle with it.
You’ll need to be able to evaluate your own writing, see where your deficiencies lie, and seek out help in those areas. An editor can help with this. A friend who is both knowledgeable about writing as well as brutally honest can help, too. An editor might be the easier path.
No matter who you learn from, whether it is a local writing teacher, an online writing course, or a book, you’ll need to be able to learn from them as well as integrate it into your own style. Shawn Coyne has a good story about someone who did the exact opposite of this. Don’t be like that person.