Hi there I3lossom,

It seems to me that if you know what is wrong, you can then single out what is right. In cases like this you should try to provide the community with more information such as what you are using the palette for. Palettes, in my opinion, are very personal; furthermore, there is not a single palette that is the be-all end-all to color palettes. It seems to me that you are feeling a little uncertain about the palette you have here, so I'm going to try to give you some specific advice, but then also some more generic advice. Keep in mind that this advice is based solely on what you've provided, so if you'd like to be more specific perhaps I can provide something better.

The palette you've provided has a relatively limited range of hues, mostly in the Red-Orange-Yellow range. This might be what you are going for! But a palette that is so narrow in hue range won't be as versatile as one that also includes Greens, Blues and Violets. Are you going for a general purpose palette, or do you really want to stick with this hue range? That is a good question to ask yourself.

Next we should talk about contrast; this ties into the last point as well. The human eye, and indeed the eyes of many other animals, distinguish form and depth by interpreting the contrast of various objects. Contrast can be used to set mood, delineate shapes in your work and do many other things. Contrast has a lot to do with perception, but a good rule of thumb when you are just starting out with color theory is that colors from different parts of the color wheel (hot vs cool, etc.) will contrast better with one another than adjacent colors. In the palette you've provided (from left to right top to bottom, ignoring white space) colors 1, 2 and 3 have a nice range of contrast. However, you might notice that colors 2, 8 and 11 look very similar, and have poor contrast. A good question to ask yourself here is: Will the colors I've chosen allow me to properly delineate shapes in accordance with the style that I am shooting for?

Let's talk about saturation next. This is essentially how intense your colors are, the less intense the closer your color is to being black, gray or white. Things that are less saturated tend to stand out less than things that are highly saturated, this can be used to various effect but one of the more obvious uses is that to make something appear farther away, you can desaturate it. Of course, many things close to the viewer can be desaturated too: raw hardwood such as maple looks desaturated even when it is right next to you. Out of the colors on your palette, 5, 7, 9 and 10 are similarly saturated. Here the question is: Does my palette give me a range of saturations that I can use to represent depth adequately? Keep in mind that having black and white in a palette can greatly increase your available range of saturations if you use dithering! The below image may help you visualize the relationship between hue, saturation and value:



I feels like I'm getting a bit long-winded so from here is a bit of general advice...

Your palette should fit the mood you want to present.
Your palette should be as specific or as versatile as you want it to be.
Your palette should not be gigantic! (This is important, less is more.)
A good basis in color theory goes a really long way. (Doing some reading, or taking a class if you can, is a good idea.)
You should study the palettes of your fellow artists because we have a lot of experienced people in our circle! (Check out syosa's palettes and DawnBringer's palettes.)

Finally here is a page hosting a pdf of one of many great color theory books: The Elements of Color by Johannes Itten

I hope this helped you somewhat, feel free to ask more questions and provide some more context if you'd like! I'll check back in a day or two.