When working from a photograph there are several very important things to keep in mind.
1. Compose your photo so you don't have a lot to rearrange when you start your painting. Working from a well composed photo will resolve a lot of your problems and you can better concentrate on painting and not rearranging your subjects and composition.
2. Use a monitor or a tablet such as an IPad to view your photo. You'll get a much better look at the colors by using it than you will be printing it on paper.
3. If you do print out your image to work from BE SURE AND USE PHOTO PAPER. Printing it on regular paper will give you a dull and practically useless reference to work from. Spend the few cents on paper and save yourself the aggravation of having to look at a poorly reproduced photo.
4. Keep in mind that a good photo will not always translate into a good painting.
5. Stay away from painting sunsets from photos. The colors in a photo will simply not be there for you in the reference photo with few exceptions. The camera is not very good at capturing the extreme lights and darks of a sunset.