1. Think composition before everything
In my eyes it is THE most important thing. A well composed photo can sometimes survive bad light, bad settings and even bad editing - A badly composed photo survives nothing.
2. Invest in an appealing watermark
A watermark can scream either professional or amateur to your followers. Even if photography is just a hobby - don't you want to be professional in the way you go about it?
3. Never post more than one photo at a time
This is a big one. No one needs to see 10 slight variations of the same scene all posted at the same time. Narrowing it down to just one that you post will also help train your eye to be more discerning about the finer points of a photo.
4. Increase your editing skills
Its as simple as this - If you want your images to stand out from the crowd, you MUST learn how to edit and edit well. I don't know of ANY professional photographer who shoots digital and doesn't edit their images to fulfill their vision. See Earth Edit for information on how you can improve your editing.
5. Learn what good light looks like and don't settle for less
Having an eye for good light will help your images no end. Try taking a photo of the same scene from afternoon through to sunset and you will see how much of an effect light can have on a scene.
6. Finish your image off properly for web viewing
It's not a necessary thing - but it does allow your image to look the best it possibly can. Just resizing an image down to web size without proper sharpening will often end in soft, non punchy images. Ain't no one got time for that!
7. Less is often more
Shoot and edit with that mentality. Leave space around your main subject and don't clutter the frame. Its like a good pizza... less toppings = more taste.
8. Rules are over rated. Know them but don't be scared to break them
Rule of thirds, leading lines, golden ratio etc.. all rules that have merit - but many of my best selling images break the rules. I very rarely think of any rules when Im out shooting. I just trust my design sense and my ability to know what looks good. At the end of the day thats all that matters - Your image needs to look good!
9. Never ever tolerate a crooked horizon!
10. Don't just take a photo.. Take a moment and create a mood. Make your viewer feel something.
This comes through composition, editing and use of light and shade. Put thought into all three and the chances are you will have an image that tells a story.
Most of my print releases have had filters used to help with dynamic range or add long exposure interest. I love my 6 stop NiSi filter - can be used in so many different situations to help create an image with a difference. Contact me if you're interested in hearing more about NiSi Filters.