Recently, I've spent a bit of time thinking about the principles that I go by in my photography. Here's what I came up with.
1. Know the fundamentals - a deep understanding of how ISO, aperture and shutter speed work together will take you 80% of the way towards being a truly competent photographer. Everything else is extra.
2. Back your data up - doesn't matter how good your photography is if it all gets deleted, right?
3. Shoot RAW - why settle for less? Because that's what JPEG is. Unless you're shooting 5000 photos of a football game in perfect conditions and you've done it a hundred times before, I'd really like to hear your excuse.
4. Glass first - high quality lenses will always, always outlast even the best bodies of today. Some of my best photos were taken on an old(!) D7000 because I had top quality glass mounted on the front of it (Nikkor 24-70 2.8).
5. Show your work - why take photos if they'll just sit in a metaphorical drawer forever? Get them out there. I don't care how. Put them on Flickr. Create a website. Show them to your friends. Email them to your relatives. Enter them into competitions. Doing all of these things will give you some level of feedback and the encouragement to keep going.
6. Always learn - reading books, watching youtube videos, experimenting with new techniques and equipment, talking to other photographers, going to classes and seminars...it all adds up and helps you keep on developing as a photographer. Otherwise, you'll just stand still and get boring.
7. Capitalize on your limits - shy of shooting people? Become the best landscape photographer out there. Haven't got the best equipment? Improve your technique so no-one can tell. Running out of light at the end of the day? Do some crazy long exposure. Don't worry about the things that stop you doing what you had in mind - let the constraints that play out on the day (and there are always more than you imagine) work to your advantage.
8. Value what you do - others may not get it or see the appeal. Ignore them. Placing a high level of value on what you do with your gear, your subjects, your locations, your processing - you name it - will turn itself into improved results every single time.
9. Change frequently - taken all your shots in landscape? Shoot portrait. Been shooting wide all day long? Switch to long glass and zoom in for a different perspective. Only ever process in colour? Do some in black and white. Only ever shoot buildings? Scare yourself and take portraits once in a while. Changing and adapting constantly keeps you fresh and the things you learn through different ways of doing things seep into all the other types of photography you do.
10. Have a sense of humour - take yourself too seriously and all your photos will be boring and staid. Keep laughing.