One can search for the "perfect" teacher or friend his whole life long to no avail.
Indeed, the ba'al teshuvah, with his ability to uproot himself socially and intellectually and to walk untrodden paths, is particularly prone to endless wandering.
"Make for thyself a master" means make a decision and take a stand.
There are well-known cases of people who were outstanding individuals in their own right, with much to contribute as teachers themselves, who, nonetheless, for the sake of their own development, accepted the authority of others they saw as being on a higher plane.
Eventually one may move on to other masters, other social attachments.
But it is important at any given point to make a firm commitment and stick with it for as long as it takes to build a stable spiritual edifice for oneself.
Such commitments need not last forever, but neither should they be seen as mere dabbling or experimentation.
Once a choice is made, it should be solidified, developed, and built upon.
As the Sages said, "He who establishes for himself a place of prayer will be aided by the God of Abraham."
The fixing of such a place, be it for prayer, for the study of Torah, or for fellowship, creates a vessel for the beneficence of Him who comes to the aid of seekers.
–Rabbi Adin Steinsaltz
From Teshuvah by Rabbi Adin Steinsaltz