Tips on cutting fresh coniferous and pine bonsai:

• The new growth on most coniferous Bonsai, such as Junipers, may be plucked back using the tips of your fingers. The leaves should be snapped off in neat pieces. All new shoots' apical growth should be targeted, and new growth should be cut in half.
• You can clip fresh conifer leaf growth with trimming scissors, but be cautious to cut in between the needle-like leaves to avoid big fleshy incisions that result in browning off on the extremities of the foliage.
• Pine trees require more specialised trimming, which may be a time-consuming operation. There's a lot more information here than there is room for. A few specialised publications on cultivating and nurturing Pines for Bonsai exist.