whanypu painting colors did you mean color theori or shadows? if you meant color theori: i can see u used a minimalistique palette. If you want your some places of your art to pop, use other colors who are completery or tridiac… if you meant shading: try making morencontrast. Do be affraid to use that black or white. Go as far as u can but whitout make it only black and black if u know what i mean. thx 4 reading! Hope it helps!

What @Steve Lenze said. Plus I would add that this is more a study of value rather than all the aspects of color. You may want to use simple shades of gray if value is what you're really after. Other than that I think it's great that you're limiting your palette to a minimal set of values as this is the best way to study. But, the most important is to keep practicing. So do a whole bunch more with the changes suggested and post for us :)

Hey Anubhav Saini, I think what will help in your quest for color is to think about temperature. Think about what temperature your light is, warm/ cool, then warm or cool off the highlights and shadows. I did a quick paint over to show you what I mean, hope it helps :)

I agree with @appo. You might wanna pick a different subject. That being said, your use of monochromatic blues to indicate the values was a nice touch.