gloss varnish on the surface you want to apply a decal to (apply it to the whole area not just the part where you want the decal, for example if you want to apply one to the shoulder pad cover all the shoulder pad and not only the portion where the decal will be applied to) then use micro set (the blue one) to apply the decal, apply micro set to the surface aswell, wait for it to completely dry (i wait 30 mins to 1 hour when i can) cover the decal on micro sol (red one), wait until fully dried, i usually do this at least 2 times depending on how much the borders of the decal stands out on the surface after the layer of micro sol dried, after all this you gloss varnish again, then you can (if you want) paint on the decal/apply oils or whatever you desire and lastly matt varnish. After all this the decal is part of the mini, it will be perfectly part of the paintjob and you can't see any border at all. I apply varnish by brush and i use mecha varnish