Thanks for the question, Bruce. Will do my best here. Two main suggestions:
First, the normal technique for sticking to a specific palette is not to add, but subtract. So, in essence, shoot normally and then take saturation out of “unnecessary” colors. For example, say you take a photo of a city and want to accentuate the yellows and oranges only— find the saturation sliders for individual colors in your application of choice and start to reduce greens, purples, blues, etc. Maybe even increase yellows and oranges. Play around with this until it feels right to you. You don’t have to completely desaturated the other colors, btw. Just decrease its importance to the overall image. Likewise, if you like the blue/orange look, your technique is to decrease green, indigo, violet. The degree of desaturation is up to your taste. And if you want to increase the orange/blue, try using vibrancy rather than saturation. It’s a bit more subtle and natural.
The next suggestion is to start to include objects in your preferable color palette as you can. If you like the Fall look, try to find backgrounds and objects with reds in them. This will help push your palette into more of your image and help the overall coloring of your image feel more purposeful.
Hope that helps!