Ok, if you like that "Painted On" look, but lack the free-hand painting skills to do it than I highly suggest these two products. Microscale Industries, Inc. Micro Set and Micro Sol. They are absolutely wonderful.
Micro Set is a very versatile decal setting solution that does several things, it softens the decal so that it can conform better to the model's surface, and can be used as a decal remover / lifter after the decal has already been put into place.
Micro Sol setting solution is for the most difficult irregular surfaces. It completely softens the decal allowing it to drape down onto the surface of the model conforming perfectly and without distortion.
Brush a little Micro Set onto the surface where the decal is to be applied. Place your decal and than carefully brush some more Micro Set onto the decal. Wait a few minute for the setting solution to work. If needed apply more Micro Set -OR- use Micro Sol for more softening strength. Once Micro Sol has been used, leave it alone, it does the work. Don't touch it before it's dry as the decal is very soft at this stage and could be easily damaged.
Here are some examples: