When you have a graphic that just needs that tad of 'spark', an easy way to improve on the visual effectiveness thereof is to apply some simple Photoshop techniques.

Levels

  1. In Photoshop, open up your levels editor (I think it's image / adjustments / levels).
  2. You will see a histogram of your image data.
  3. From the right-hand side, there is sometimes some blank space before the graph starts.
  4. By moving the right-hand pointer to the edge of that graph data you immediately improve brightness quality without losing picture quality.
  5. Once you move the pointer to within the graph data you will start seeing a degration of quality (your whites becoming too bright).
  6. If you move the left-hand pointer to the right, your dark colours will be accentuated, but use that sparingly.
  7. The middle pointer changes overall brightness (like white balance), but you usually don't have to change that much except if the overall picture quality is quite dark.

 Saturation

  1. To improve the colours in your picture, open up the saturation editor (image / adjustments / hue/saturation).
  2. By moving the saturation slider to the right about 10-20 points increases the overall colour richness of your image.
  3. If your picture seems to have too much of a specific colour, you can select specific CMYK to change that.
  4. You can also get some interesting effects by changing the hue when having those selected, for instance you want to change the blues in your image to a richer blue etc.
The best idea is to play around with these settings and never to overdo it. Use different settings and do print proofs as onscreen colours often look different than print when working in CMYK.