Try shaking and stirring the bottle really thoroughly before you spray (it seems obvious, but you'd be surprised how many people don't do it enough. I know I don't half of the time). If you've already done that or it doesn't work, try putting it on in multiple thin layers. You don't have to get full coverage the first time you spray or brush on a coat.
And the final tip is to let everything dry very well before touching it or painting over it. Enamels take a bit longer than acrylics to cure so leave it overnight between coats or before handling.
I probably sound like Mr. Obvious here, you've probably done all of this already. But, that's all the advice I've got at this point in time.
hope it helps.