Are the decals new? if so then you can forget the dish soap. Newer adhesive is re-position-able for a short period and you don't want the left over soap residue any ware under the decal.
If you really want the decal to last you'll want to get one of these edge sealers. http://www.signsplusbanners.com/item...quid+Laminates
Sorry Dr. but have to give different instructions.... was area with dawn dish soap - enough soap in water to feel slippery - this will remove any wax or residual grease. rinse...rinse rinse...
Then wipe down with 30% isopropyl or moonshine
- this will remove any residue and not leave and haze residue. If you want to feel safe to re-position - a little distilled water.
Before you apply...place decals on a smooth face up so you can see decal. use a credit card to rub decal against transfer tape. This will ensure a that decal transfer well to transfer tape.
Get some masking tape to make a hinge on the transfer tape...
This one is pretty good. http://www.youtube.com/watch?v=0uUu-SCz1OY
I work for a vinyl printing manufacturing company... most important...take your time..