Tamiya XF-2 Flat white problems

I'm trying to get some xf-2 flat white paint on the plastic. Problem is, it looks aweful. The paint doesn't cover the plastic all too good.

I guess the answer is primer. But, is there another way? I'm trying multiple layers now, it works, but it doesn't look smooth.

You using a brush or an airbrush? Primer would help it stick better to the plastic and an airbrush would help get a nice even coat.

I'm using a brush.
It looks kinda clotted, as if the paint dries up fast while i'm painting.
Bringing a drop of paint on the plastic and let it spread out seems to work.

Just use white primmer only for the part you are painting.
That flat white is a bitch of a colour to use

Use primer and airbrush for better coverage.
I used flat white for Porsche 959 pressurized magnesium wheels