In case you ever find yourself in the same situation, or so it might be helpful to someone else, here's my little tutorial to explain to my fans how to properly glue. I'll explain a few things that haven't been mentioned or seen in tutorials or video-tutorials.
How to stick small-medium sized vinyls (By Mikonos):
1.- Clean the surface where the vinyls will go well.
2.- Prepare a solution of water and soap in a bottle with a spray applicator, preferably.
3.- Clean your hands well with soap to handle the vinyl.
4.- Wet the surface, your hands and the vinyl on the adhesive side with water and soap. Follow this order. At this point, you will be able to touch the vinyl on the adhesive side without any problem.
5.- Place the sticker on the surface without applying force, moving it gently until it is in its final position.
6.- Apply force with a plastic card or a vinyl applicator to carefully remove the water between the vinyl and the surface. Apply force from the center of the vinyl outwards.
7.- If you don't have much experience, it will be normal for water bubbles to remain between the vinyl and the surface. Don't worry, it's just a matter of a few weeks before the water evaporates completely and the vinyl looks perfect.
NOTE 1: You don't need transfer paper, especially if it's not transparent and because there are no loose vinyls that need to be kept at certain distances from each other. You'll do a much more precise work handling small or medium vinyls this way, especially when positioning them.
NOTE 2: With vinyls with transparent parts, you should use soap and water to avoid the risk of matte areas or defects.
Cheers!