You need to make sure the surface is clean and dry before you stick it. Any greasy dirt or water will influence the perfection of the sticker. Sometimes there might be some bubbles appear in big stickers, if this happens please remove the bubble or just pin it. When the wall is wet due to some unexpected reasons, it might have bad influences on the sticker, when this happens please dry the wall and the sticker with an air blower or simply stick it again when the wall is dry.
