Extinguish any candles you have used during your spells. DO NOT blow them out as this disperses the magick, thus weakening the spell.
Absorb any excess energies that are inside the bubble that failed to be used or focussed into your spell's purpose. This will help you revitalise. If you performed the spell properly you will probably be feeling quite exhausted by now. Just visualise this.
Once this is done, see the dome slowly collapsing (starting at the point directly above your head) back into your circle on the floor. Then collapse it anticlockwise (widdershins) into the point from which it was formed. Now extinguish (don't blow this out either) the candle.
The circle is now dispersed and it is safe to leave.