1. Practice. You've heard it before, and I'm reminding you again. Practice, practice, practice. Practice makes perfect. Just like Malcom Gladwell proves in his book Outliers, it's all about the time investment. 10,000 hours baby! Put the time in, and you will be the best of the best.
It doesnt matter if you use the best equipment like a Nikon D4 or a Canon 1Dx, or you use a bargain priced Sony NEX-3N or Canon T5i, it's the photographer that makes the photo. And the skilled photographer, the one who has practiced countless hours and honed their craft, can take a great photo with just about any camera or image making device.
2. Learn lighting. Even a single $59 Speedlight used off camera with an inexpensive $40 radio trigger, heck even an old school flash cord, will make all difference in the world to your photo if you know how to light it properly.
I am constantly amused how many photographers advertise themselves as "natural light" photographers. Basically they're telling everyone that they don't have a clue how to do lighting, which in effect is saying they aren't really that great a photographer because they haven't taken the time to learn one of the most important aspects of the craft.
Sure, there are few amazing "natural light" photographers, but they are also the ones who know photography inside and out, are skilled at lighting, and have then chosen to shoot predominantly without artificial lighting. There are VERY FEW of these photographers out there. The bulk of photographers who say they shoot with "natural lighting" just don't know how to use artificial lighting, hence they try to make themselves sound artistic by trying to make their ignorance sound like an advantage.
3. Get it right in Camera. In other words, shoot it properly when you take the picture. Know your settings. Know your equipment. Know your lighting. Anticipate your subject.
Poor shooting, and then saying you'll just fix it in post with Photoshop or Lightroom, is lazy and degrades your skills (if you have taken the time to acquire any. A lot of times when a photo isn't shot right at the time, the photographer did it out of ignorance because they didn't have the skills to begin with. See #1.)
4. Be prepared. Extremely critical for the professional photographer, but still very important for the amateur enthusiast photographer, be prepared is a great moto to live by. There's a reason it's the Scouts' motto!
Have your gear prepared prior to your shoot, batteries charged, memory cards ready, lenses cleaned, cameras synced.
If you're going out to shoot a landscape at dawn, know your sunrise times and scope out where your best vantage point is ahead of time.
If you're going out on an assignment for a tricky client shot, run the scenario through in your head before the big day. Try setting up a similar shot at home or in your studio and figure out possible problems and solutions ahead of time.