Actually, lama (which is the
Tibetan version of the
Sanskrit term "guru" and has the literal meaning of "
heavy one" in the sense of weighted with wisdom) is a term applicable to thousands of senior Tibetan Buddhist monks and is also carried by quite a few Westerners as well.
In the Karma Kagupa sect of which the Karmapa is the head, the common qualification is to undergo a three-year retreat during which one studies and practices the basic curriculum of sadhanas associated with various yidams so that when one gives an empowerment (wangkur) one knows which mantra goes with Green Tara and which with White Tara. (Of course many lamas have practised several such retreats.)
The standards vary from sect to sect, but this is the general approach.
This is not intended to impugn the sincerity or qualifications of any of the thousands of lamas around the world but just to clarify the point of "qualifications" and rarity of the use of the term.
sources: conversations with Ven. Tenzin Gyatso rinpoche (Dalai Lama); the late Ven. Rigpe Dorje rinpoche (the sixteenth Karmapa), the late Jigdral Yeshe Dorje rinpoche (Dudjom rinpoche, a former head of the Nyingmapa) and dozens of various lamas of the four major and a few of the minor achools of Tibetan Buddhism such as Lama Zasep Tulku. Tashi deleg, guys, if you're reading this.