There are many things to say about clean code and it might not be something new or be revealing to you, but I want to share a very helpful approach, which can help you to write nice looking code.

Background

Let's imagine that we have a piece of software that allows us to create documents with some indexes and file attachments. Our task is to listen to an event, like DOCUMENT_CREATED or something like that, and then carry out the following actions: 

- Validate the document and move it to the Error folder if needed.

- Send an email to the administrator.

- Move the document to another folder based on its category index.

That's all, and enough to screw up the code.

A Reasonable Approach

1. Do not write any implementations first.

2. Instead, write out all your logic using only method names (i.e. descriptions).

public void onDocumentCreatedListener(Document doc){
  if(isValid(doc)){
    sendEmailNotificationToAdmin(doc);
    moveToCorrectFolder(doc);
  }else{
   moveToError(doc); 
  }

}

We don't even have logic methods in the above code, but our IDE can create ones instead of us (ex: Eclipse).

The method above is the same as describing the each step in this process, as it allows us to think about each step.

3. Write implementations.

4. Fun!