Your stickers and surface may have been contaminated if you were trying to apply it by hand, therefore you have lost your adhesion. For best results with stickers, prep the surface with alcohol, let it dry, and apply with a tweezer. Press down using a cotton tipped swab. Use latex/nitrile gloves to be extra safe. Work in a warm environment so that the adhesive sticks better.
Your fingers contain a lot of grease (no matter how well you wash it) and a lot of dead skin cells which will stick to the adhesive causing the adhesive not to be as functional anymore.
For stickers that have completely lost their adhesion use a light amount of nail polish as others have recommended. Alternatively, using tweezers to hold the sticker, spray the adhesive side with a light coat of spray-on adhesive, then attempt to apply as normal.
Any other adhesive options may cause significant changes in the weight/performance/shape of your Beyblade and is not recommended. This includes but is not limited to: craft glue (stick or bottled), wood glue, cement, "Super Glue", tape (no matter how thin), "Gorilla Glue" and epoxy.
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As for Tamiya and other decal products, here is my advice as a semi-retired PlaMo artist:
Do NOT use Tamiya liquid cement. It is very corrosive and highly reactive with most plastics and will melt the surface and decal's design. Cement is usually used in PlaMo/GunPla to permanently fuse two pieces by melting them together. The ugly deformation that results from this is sanded away and painted over never to be seen again.
Decal protection products such as Micro-sol or Mr. Mark Setter/Softener are also not recommended. These are slightly corrosive in order to help a water slide decal fuse with its surface better. Takara Tomy's stickers are not decals so you may end up marring or disfiguring the surface since it is colors printed onto a adhesive surface. You may see some light success by applying it to the backside but it may not be an optimal solution.
Thanks for reading~
Emperor Forneus = Sharknado ♥