Before cutting with the Boline, attune with the plant through visualization.  Feel  its energies.  As you cut, say these or similar words:
"O little plant of (name)
I ask that you give of your bounty
that  it may aid me in my work. 
Grow stronger by  my  stroke,
stronger and more powerful,
O plant of (name)!"

If it is a tree, substitute the appropriate word (i.e., O tree of willow).

Gently cut only what you need, and never from very young plants or more than twenty-five percent of the growth.  At the base of the plant leave an offering: a silver coin, a bright jewel, a bit of wine or milk, grain, a quartz crystal and etc.  Cover the offering and it is done.

~from Maat's Book of Shadows