This is a very short, quick and simple spell to do. It can be done anywhere at any time (though during the waning period of the moon is best as that is the time for banishing magick).
All you need is yourself, an intent, a person in mind (it helps to have a picture of them if it is difficult for you to visualize them) and your finger ( I'll explain).
Draw a banishing pentagram in the air with your index finger. This is done by drawing a five pointed star backwards (the opposite direction you would normally draw it, not upsidedown) Draw it while saying: Let this pentagram banish all ill health and negativity from (the persons name). I find that there is no specific number of times you repeat this process, it becomes as many as you feel is enough.
I have seen this spell work very well as I did it when my Dad was sick and my Grandpa was in hospital. My Dad was better by the next day and my Grandpa had a very speedy recovery (although I also think there was another force at work there - my Grandma and Great Aunt prayed to a saint in the Netherlands). So as you see a spell doesn't have to be very elaborate for it to work well.