You've probably already practiced filming on your own. Whether you're in school or learning by yourself. But just like a sport or a muscle, you have to practice and exercise. Invest in a camera and some equipment. Your smartphone isn't the worst camera option you have anymore. Provided you have a relatively new smartphone. But it still won't compare to even a DSLR camera. If you can, invest in a DSLR camera. DSLR's made in the last few years can usually shoot HD video. Additionally, these are cameras that are great for photography. And since you are a cinematographer, photography is one of your best friends. Learning photography will be invaluable to you if you want to be successful as a cinematographer. You will learn framing, composition, exposure, texture, etc. All these elements that are crucial to getting a great photo also apply to getting a great shot. Then film those shots. This will be really easy if you have a nice DSLR with you. When you're out and about during your day, take moments to look at a nearby landscape or city street. See how it looks to you. Imagine you are filming this location for a movie. Take some photos of the area you are studying. Take notes on how it makes you feel, what's happening in that moment. Maybe you're on a busy street in a city right before it rains. Or you took the long way home and are standing by a field of tall grass as the sun sets. What emotions do these images conjure up in you? What kinds of scenes could be taking place here? These are questions you should learn to ask yourself and answer at any given moment. Jot down the answers into a notebook and write the time and place. Snap a couple of photos or film a few seconds. . If you want to be the director of photography, you need to learn to direct, both your camera and people. Come up with an idea for a short film and make it. You can choose to take on all the roles or stick to a few. Get your friends to help you. This will be pretty easy if you are or were in film school. Just get out there and start making short movies. Try for three, or five, or ten minute films to start. You don't need to make the great indie masterpiece. The fact is, you probably won't, at least not for a while. So don't worry about getting everything right and perfect. Use what you have at your disposal and get out there. Actually shooting something will put you ahead of most of the people who dream of becoming a cinematographer but never take advantage of that dream. You need to learn how to tell a story with your camera. The best way for you to do that is by trial and error. Yes, schooling and tutoring and studying will help you. But to really develop your talents, you'll have to fail and make some mistakes before you realize how to best get what you want and need in your own way. Once you have a little bit of practice and work to show, it's going to be time to get yourself on a professional set. Have realistic expectations for getting on a set. No one is going to pull you out of the blue and hand you a camera. You'll have to slowly work your way up. It doesn't matter how you get on set. You may not even be able to get a job related to the camera work. Apply for any set jobs that you are qualified for. You can be a production assistant, camera operator, lighting technician, craft service personnel, or even an extra. Your goal isn't to get a shortcut to fame. It's to get exposure and learn how a real professional set operates. Get on set and take everything in. It will be eye opening. You will not only see how the filming happens but how people act and behave. You will come across extras who think this job is going to bring fame. Production assistants who are annoyed by the extras. Directors who act like tyrants. Camera operators who are quick and easily annoyed if anyone gets too close to any equipment. Build relationships with gaffers, grips, production managers, producers, and directors. If you get on set, let everything you experience soak in. Then stay out of the way until you're needed. While there will be a lot happening, it will also give you the opportunity to see the magic happen. Pay attention to how the lighting is set up. How the crew moves props and materials around to get a tough shot. What lenses are used and why certain ones are used for certain shots. Learn from what people do right, and what people do wrong.

Summary:
Start shooting. Take notes everywhere you go and storyboard shots of your surroundings. Make your own short films Get on a set.