Changing the colour of your psd to fit the entire cover is such a key that I have figured out over the last couple of days; some working while others didn't.

For example, here is a cover win a psd that I have toned down a lot:

As you can see the blue just looks super odd and really doesn't fit the tone of the cover at all; here is after I have changed the colour of the psd to fit the cover:

It now looks better doesn't it, it unites the cover and makes it look so much better and I personally love it.

Here is a bad example of changing the colour of the psd:

Yeah, doesn't look good does it; here is the perfect amount:

Here are some more good examples:

(I LIKE PURPLE SO DON'T JUDGE ME)