There are quite a few different consecration rituals but this is the one that we usually recommend. There is no one right way, nor is there a wrong way, so feel free to adapt the ritual if you wish.
You will need a white candle for the consecration flame, water and incense.
Cast your circle.
To consecrate the tool, the elementals may be used.
Pick up the besom, saying: "I have chosen this besom to assist me in my work."
Visualize the besom being cleared of any negativity.
Continue till the besom feels clear to you.
Now visualize positive energy flowing from you, down you arm and into the besom.
Visualize a strong white light flowing through your body to the tool. Feel it absorb the positive energies.
Point the besom towards the North, saying: "May the powers of the Earth cleanse and fill the besom I have chosen."Touch it to the pentacle, saying: " In the names of the Goddess and God (use any names you wish), I bless and make sacred this besom, tool of my craft. I charge this besom by the element of Earth."
Point the besom to the East, saying: "May the powers of the Air cleanse and fill the besom I have chosen." Pass the besom through the smoke of the incense, saying: "In the names of the Goddess and God (use any names you wish), I bless and make sacred this besom, tool of my craft. I charge this besom by the element Air."
Point the besom to the South, saying: "May the powers of Fire cleanse and fill the besom I have chosen." Pass the besom quickly (the besom itself is obviously flammable) over the candle flame saying: "In the names of the Goddess and God (using any names you wish), I bless and make sacred this besom, tool of my craft. I charge this besom by the element Fire."
Point the besom to the West, saying: "May the powers of water cleanse and fill the besom I have chosen." Sprinkle the besom with a few drops of water, saying: "In the names of the Goddess and God (using any names), I bless and make sacred this besom, tool of my craft. I charge this besom by the element Water."
Then say: "This tool is now ready, being consecrated and charged to assist me in my work. So mote it be."
Perform other workings if you wish, then close the circle