Hello,
Can some one please tell me how to use mesh fill tool correctly??
What do you mean by correct?
Artistically I'm not sure there is a correct but from a technical standpoint there are things that make it easier.
The questions?
Is your work going to end up being RGB
Is it going to be CMYK?
I suggest before starting any document that you sett the application primary color mode under tool menu/color management/default settings to your desired model, RGB or CMYK.
Then when you start a document make sure the document primary color mode follows suit, it should but if you open a nold file it will not, if you need to change it go to tool menu/color management/document settings to change it.
I would start a mesh with a circle and convert to curve, this gives you best control over the nodes, fill the entire object with WHITW, RGB mode R255 G255 B255, CMYK mode, C0 M0 Y0 K0, this will set the dialogs to you primary color mode.
I would then avoid the eyedropper tools, you can use them but only from the palettes from the workspace or the document palette, use the color sliders is the best way. You can drag and drop colors from the palettes to the mesh but remember RGB for RGB and CMYK for CMYK ONLY!