Rule #1
Decals and stickers are two different things.
Different application
One difference between decals and stickers is that decals are formed in several small pieces of adhesive graphic. When a decal is applied, there is only the graphic itself on the surface and nothing else, which gives out a nice look. This difference requires an application technique very different between the two.
The sticky part
Decals and stickers have an adhesive and so both are sticky. Since both of them are sticky, most people do not make distinction between the two.

When you purchase a decal on the web, that decal always comes in one piece that can be separated in three layers. Before applying the decal, let’s take a look at what it is composed of:

Decals parts
Step 1 Rub the decal to be sure the transfer tape is properly adhered to the graphic.
Step 2 Clean and dry the desired area. Decals will stick best to clean smooth surfaces. *This step is crucial for interior application (reversed decals only), because if left, dust will be noticeable on the other side.
Step 3 Remove the paper backing slowly making sure the graphic stays adhered to the transparent transfer tape.
Step 4 Use a hard edged object like a credit card to make sure the entire graphic is fully adhered to the surface.
Step 5 Slowly remove the transfer tape. Making sure no part of the graphic remains on the transfer tape.
Step 6 Check for air bubbles. In most cases air bubbles can be worked to the edge of the sticker, but if not, a pin hole will allow the air out and become virtually invisible, once the bubble is gone.

Stickers are much easier to apply. You just peel off the sticker, apply and you're done. Watch the video to see the differences between the two.

What is a decal sticker
What is a decal sticker © 2014