2. Know how you camera works.
This goes right along with manual mode and knowing HOW your camera works is going to be key to improving your photography. Grab a cup of coffee, your camera + your camera's manual and spend the day getting to know your camera. Read about the different functions of your camera and how they work. The manual does an AWESOME job of explaining what the various functions are, how to change them and what they can do for your images!!
Important functions to learn: white balance, focusing modes, metering modes.
3. Know the exposure triangle.
Part of shooting in manual mode is knowing what aperture, shutter speed and ISO are and how to make them work for your images. Having full control of these settings is going to let you create your images the way you visualize them!
4. Study your favorite images + images from your favorite artists.
I mentioned this yesterday when we chatted about "finding your style" and it I think it totally applies here. Having artists and people who inspire you are so important. By studying their work and dissecting what you love most about their art, you will begin to hone in on what style you like. I definitely AM NOT suggesting you copy another person's work or try to recreate a shot EXACTLY as they created it. That's no fun. Instead, look at the elements of their work (like lighting, composition, framing, lines, etc...) and let those INSPIRE you.