Be consistent in the following:
*Topics - You can have more than one writing niche. But if there are no clear areas of expertise in a writer, it will be harder to develop a consistent audience.
*Style - Your writing style should match in all of your work. Frequent readers should be able to tell that a piece is written by you just by the style.
*Voice - Be yourself in all of your work. Let your writing light shine so that readers know the real you. The real you should be consistent in all of your work and should match your true writing personality.
*Advice - If you advise readers to do one thing one day and another the next, this causes confusion. Be consistent in methods and beliefs that are present throughout your writing.