Hi sean, my suggestion is, try to learn value in b/w first, so you’re color will be more greater and not flat, as Nathan Fowkes said “If you get the value right & if you got the color temperature right, you got the color right”, try to studying value alone itself first before jumping to color, many good book is good to learn, Andrew Loomis are recommended stuff, here’s my paintover your painting so you can see your value is wrong
(hope you don’t mind I paintover it) :
Before, This is your value

After
Im slowly building all the value structure here (face only), adding highlight on her eyes, make the light more pop on her hair, and make it the BG more dark to make the focus on her face or make her face pop-out even more

A little artistic touch to make it more interesting to the focal point, which mean her face

okay, im recap my suggestion to your painting :
- Study the value first before jump to color (use hard edge brush and blend it with charcoal brush with color picker, do not use smudge to blend)
- Careful with the brush stroke edge
- Don’t stop to study
- Keep it up
- Good Luck