Thanks for the question! The thing I think is most scary about color is you have SO many options with it. So my best advice is to limit those options. Try a simple complementary palette. That means you only have two hues to choose from (any 2 hues, so long as they're at opposite ends of the color wheel), and you can work within their ranges of gray to create a simple color harmony. This palette is a great intro to color because you basically can't screw it up: it's only 2 colors! You will also garner an appreciation for the power of grays when you use this palette, as that's where most of your colors will exist. My favourite complementary palette is yellow vs. purple. Yellow tends to capture sunlight well, and purple tends to capture the cooler shadows well. Obviously the sun isn't just yellow, but this is a good starting point to capture nature with. Another easy-to-use palette is the Analagous Palette. That's when you choose 3 or 4 neighboring hues on the color wheel and let your painting exist entire within that spectrum. Again, with so few hues to choose from, you're more likely to be creating color harmony and less likely to pick "wrong" colors. While limited palettes help ensure you don't screw up your color choices, you CAN, however, easily screw up your values and lighting. If you do that, no amount of color work will help. I haven't seen your work so I don't know for sure, but the difficulty you're describing sounds sneakily a little more like a value issue than color. I see this a lot in my students' work, too - that is, the thought that it's a color issue when really the values don't read. So make sure that you fully understand your picture's values first! This means clear light and shadow shapes, and then whatever subtle modeling you do with in those light/shadows, you make sure those values have clear shapes, too. If you are viewing your image in grayscale, that picture should read as strong 3D form. If you want to test this, simply paint an image of a sphere casting a shadow onto a table. That is very easy to draw/paint, so you're more likely to get it right. Then you can experiment all day with color options! So, back to the complementary palette. After you've tried that, then try adding a 3rd color. Usually this is called a "Split Complementary Palette" and it's where you take one of your compliments, and choose a color on either side of it. So orange splits off into yellow and red, and you still have the purple on the other side of the color wheel. Give that palette a shot! I don't mean to advertise here, but I just released a class that talks all about this stuff: 'The Color Survival Guide,' available right here on Proko.com!