Introduction

Taqlid means acting according to the opinion of the jurist (mujtahid) who has all the necessary qualification to be emulated.
So you do what the mujtahid's expert opinion says you should do, and refrain from what his expert opinion says you should refrain from without any research [in Islamic sources] on your part.
It is as though you have placed the responsibility of your deeds squarely on his shoulders.

Among the conditions which must be found in a jurist (mujtahid) who can be followed is that he must be the most learned (al-a'lam) jurist of his time and the most capable in deriving the religious laws from the appropriate sources.