Preparation and concluding for healing or meditation

In order to work safely and effectively it is good to get into the routine of preparing for your healing, meditation or spiritual work.
Here are some suggestions, which are tried and tested and known to be effective for most people.
Energy Cleansing
This can be applied to your own energy field [aura]; the objects [such as crystals] that you might use for your spiritual work and your sacred space [or altar].
Sit quietly and use the following phrase:
“May any and all negative, harmful or damaging energies be cleansed from my energy field, this space [specify] and all objects within it”
Then visualise an angelic being with a fluffy duster flying around and brushing away any unwanted or negative energies.
Dedicating your sacred space. 
Sit quietly within your space and use the following phrase:
“From this point forward only the highest and finest of healing and light frequencies may enter or leave this space.”
If you wish you can do the same for your personal energy field and any objects you may use for your spiritual work adjusting the phrase accordingly.
Sit quietly and allow your focus to come to your feet. Be aware of your contact with the ground. Feel your feet become heavier and sink a little into the floor. Be aware of all points of contact with your seat bones and allow them also to become a little heavier and to sink a little deeper into the seat or floor beneath you.
Centre within your space
Sit quietly and imagine you are surrounded by an opaque geometric shape [square, oval, sphere, triangle, pyramid – go with the first shape that feels good]. When you have a clear sense of the shape you are in, allow yourself to float within the space until you have an equal distance above and below and to either side – you are centred, within your space.
Link to the Divine [Source, God, Grace, Universal Energy]
Sit quietly and imagine you have a thin stream of light descending from some distant point in space [a star maybe] and infusing your whole being through a channel which has opened in your energy field above your head. Allow this stream of healing and light energy to increase in flow a little.
Concluding when your healing, meditation or spiritual work is complete.

Sit quietly and allow your connection to the Divine light source to lessen, repeat the grounding and gentle cleansing exercises above.

Remain still for a further few minutes and gently allow your focus to come back to your physical awareness of your surroundings.  Gently begin to move about, maybe do a few gentle stretches before you resume your everyday tasks.