The spray bottle is one option. It is important to keep them hydrated. It is hard to get them to drink standing water. They need to see motion. I have trained mine to drink water from the lavatory if I just leave a small trickling dripping. They adore this method and eagerly scramble to get their fill. I do this at least once each day. They are sooooo cute when they do this.
In reality, misting only dampens their skin and does little to provide good hydration. A good bath every few days will do more for hydration than anything else (unless your dragon drinks water, which most don't). By a good bath, I mean one where your beardie's vent (the slit where he defecates) is completely submerged for 15-20 mins.