How often has someone (well-meaning indeed) looked over your shoulder at your art and expressed a concern that something is wrong; that tree is not in the same spot or that building is a different color? You know the scenario.
As a beginner, I painted everything exactly as it was presented. I did not have the experience or skills to, good heavens, change something. Though my art teacher once asked me in a still life class why I had changed the color of the cloth. I wanted it to match my kitchen.
But as we develop our skills, our confidence grows, and we know that to create better compositions, we need to create masses consistant with planes, balance, better lines and lead-ins.
And we are free to remove the unnecessary. This leads to, in my opinion, one of the harder lessons. John Carlson's Guide to Landscape Painting ( a bible for any artist) has a wonderful illustration of how you can take one scene and focus on different aspects. Make it ABOUT something.
And you grow your skills in color choices. James Gurney has written a great book on Color and Light that clearly demonstrates how to choose a limited palette to create harmonious paintings.
Take time to enjoy a history tour of your artwork. See how your skills have grown and you have developed a style. And sometimes, it is good to switch it up - step outside your comfort zone and try something new.
For anyone thinking of starting to paint - don't be intimidated. Rules will come. Just call it coloring - we were not afraid to pick up crayons as children. Have fun.