If $A$ is an arbitrary element of the general linear group $GL(2, q)$, is there a way to determine the order of $A$ without having to compute matrix powers?
The "brute force" method works fairly well. There are $q (q + 1) (q - 1)^2$ elements in $GL(2, q)$. At worst, you could check all divisors of this. Using this question it's possible to limit the search to the divisors of $q(q - 1)$ and $(q - 1)(q + 1)$. However, I am slightly unsatisfied at having to compute the order this way.