This is not necessarily important to you right now, but it will become important to you and all those who want your advice on who they should study under and how you your-self can become a good teacher.
As an initial test for a prospective teacher look for these three points; first discern the orthodoxy of the teacher’s approach, secondly observe the teacher’s students to see if they have benefited from his instruction and lastly a truly good teacher does not destroy the sight of the student but instead opens the possibilities and shows them their true nature. Other points to look for is the teachers own attainments, a good teacher is one whom combines understanding and practice and has no lingering delusions, he or she has a unified mind and body and will thank those for praise and will take blame into account but will not have his actions moved by either. Also make sure the style of teaching the teacher incorporates matches your temperament and brings out your potential.
To apply these teachings to your own search for a good teacher check the credentials of a potential instructor, do their actions match their words? What was their training? Have they been accredited by another reputable teacher? If you can confirm these with others do so. Lastly, be careful and don’t immediately study under the teacher, watch them carefully and then use your common sense on whether to study under them or not.