If the family of pink was to be chosen as a display cake, a regular 
shade of pinkwith a matching shade of regular pink might be chosen. If a burgundy color was chosen as the base board, the shade of regular pink might be used.  However, if the base board was covered in florist foil using the color burgundy, a similar shade in the burgundy family could still be used by matching colors and not just using the burgundy color straight from the jar of food coloring.

How?
Take all the colors in the pink/burgundy family and place them in front of you. Notice that the foil does not have an orange tinge.  Therefore, remove any food colors that have an orange tinge.  Now, place the blue and the purple families in front of you. 

Royal and buttercream decorations:  Take a bit of royal or butter cream and begin to use paste food colors and/or powder food colors and mix the  colors into the frosting until you have the desired shade.  Add more white frosting as needed to lighten the color if necessary, and to create more of the frosting in the dark shade that matches the foil.  From this "base color", the various shades (light, medium, medium-dark, etc.) can be created to use in the various decorations on the cake.

Gumpaste and fondant decorations:  If petal dusts are to be used, place the colors in front of you as described, above.  The various colors (powder food colors can also be used) can be mixed with cornstarch or white petal dust to make the final "base shade" lighter if needed.  Use cornstarch or white petal dust to make the various shades of the colors of the decorations. 
 

Leaves:  Make a "base shade" of green.  Use either frosting or petal dust (powder food colors can also be used) to create the various shadings of color.  If using royal or buttercream, place the various colors into the decorating bag, carefully.  If using petal dust/powder food colors for fondant or gumpaste, make various shades of the family of such that you need such as greens for leaves and use these colors to dust onto the decorations using an artist's brush.

Flowers:  Use a variety of shades of a color for each petal.

Did you ever look at a cake and say, "Oh, how beautiful"!  And, then notice the colors and the appealing look.  Was your next thought, "How lovely!  The colors are beautiful!

Matching and blending colors is very important in designing and decorating a cake.  For example, if pink, purple, teal and green are mixed individually and used to create the decorations, that is exactly what one will have:  pink, purple, teal and green decorations.  What does this mean?  It means that all items are individual and not blended.

A trick that the eye will notice, but not the conscious mind, is to take a touch of each of the colors after they have been mixed with the buttercream and put that touch in each of the other colors.  You will still see pink, for instance, but each of the other colors that were used in the cake decorations will be in the pink color.  Of course, not enough to notice, but enough to have the colors all blend together as a "family".

Gumpaste & Fondant
Petal Dusting

The cake, above, has my Popup Flowers"  technique as well as my "Puffed Embroidery"  technique.

Mix petal dust (and/or powder food colors) to create a deep shade of pink to match the cake board.  Lighten this into 4 more shades of pink making sure the last shade is a very very light shade.

Hair:  Use light yellow petal dust to "coat" the entire section of hair.  Mix a tiny dab of one of the pink shades in with a medium shade of yellow and dust different sections of the hair.  Now, go over the whole section of hair, lightly, with a gold shade of petal dust.

Top Border:  Start from the outer edge and coat each section with the next to lightest shade of pink.  Add the next darker shade of pink and start from the outer edge and dust inward covering 3/4 of the section working on.  Use the next darker shade and start from the outer edge and dust inward covering only 1/2 of the section working on.  Now, use the deepest color and touch up the outer edge only for contrast.  Use the lightest shade to gently coat the entire section working on starting from the outside edge and working inward.  Now, touch up the edges with the darkest color.  This procedure color blends all the shades in the area working on in a nature manner.

Stamens:  Use the same method as for the hair.

Flower Petals:  Use the same method as for the top border, but only the number of shades desired.

Bottom Border and Ruffles:  Use the same method as described for the Top Border and Flower Petals.

Pearl Dust:  Use pearl dust to create a satin-look.  White pearl dust can be tinted with the custom-made, color of petal dust to create the satin-look color of choice.  A light shade of pearl dust can be dusted onto the decoration and then the various shades of color from the custom-made petal dust can be dusted on top to create another, natural, eye-appealing look.