Find Your Niche: Be a Subject Matter Expert on one area of Photography. With so many aspects to choose from your heart and gut will guide you, your next step is to begin mastering it. God, we love’em all, don’t we? but let's face it, you can not be in “great” in everything for various reasons, at least for awhile, focus on what inspires you then venture out from there. One year I hiked 32 miles of local trails from early spring to winter with my macro setup shooting flowers and small things, I was inspired to do so for many reasons, to capture the natural beauty and wonderment of these varied flowers and insects that flourished in and around me and I never really noticed until I got behind a Macro lens.
Find a Mentor: Follow another photographer - I don't mean stalking, if he or she has a site or channel, tune in and pick up some pointers. Look for someone who actually does shoot and not just talks about shooting. If you want to master flash photography - check out Joe McNally.
Invest in good gear: This is a tough one. Chicken and the egg - do I upgrade my camera or lens? I recommend you buy the best lenses you can afford, once you have the basic three good quality lenses then shoot for a pro-level camera body upgrade. My must have 3 are 70-200 f2/8, 24mm, either an 85mm 1.4 or the new 105mm 1.4.
Take on a Photographic Challange: Many of us learn through trial and error, but you don't want to be in learning mode when someone else is depending or paying you for work. So, put something on your calendar and plan for an event to shoot at without worries of failure, could be a sports event - bike race, foot race, soccer game, or festival, or if you live close to a larger city - some street performers. If you suck at flash photography, take on a session of flash shots.
Teach someone else: Teaching helps you learn as well because you prepare yourself for the topic you are going to teach. Heck, teach yourself how to set up custom menus if you have not already done so.
Break old habits: Sometimes we bring old habits along with us over the years or get sloppy in our work habits. I love to go out and do bird photography, but I also know my shooting technique needs to improve - because I don't think through my action to acquire a "better" image. For myself, patience, and slowing down is what I need to improve on when doing bird photography.