This is just something I drew for practice, a simple candle.

Needs shading. The candle would be much brighter and shinier near the flame. At the base, the candle would be darker. See ref pic at candle-flame-and-reflection3.jpg
I agree with Jmurph, I did a small edit according to what he said.

^ that edit won't help you much

I removed the dithering and shaded it based on depth and highlights and all that stuff you consider when shading objects

It's a really common misconception that AA and dithering are your go-to tools for making good pixel art, but in reality they aren't 100% necessary depending on the piece you're making. Dithering is usually better for texture, and AA will come more naturally to you with experience, so don't force it

Your lighting is horrible, babe. You need reflected light.
^ this