We consider power allocation (PA) and relay positioning in a dual-hop decode-and-forward relaying system over Nakagami-m fading channels. We investigate adaptive power allocation (PA) with fixed relay location, optimal relay location with fixed power allocation and joint optimization of the PA and relay location under transmit power constraint in order to minimize outage probability and average error probability upper bound. Results show that the analyzed adaptive algorithms outperform uniform algorithms and direct transmission. It is also found that as the source destination channel is getting better, the less power will be needed to allocate to the relay node in order to satisfy the optimization criteria. Numerical results are presented to verify our analysis1.