Wireless sensor networks are characterized by collections of small, low-power nodes that collect information about the physical world. Concurrent transmissions caused by the well-known hidden terminal problem result in collisions and packet corruption. Since corrupted packets must be retransmitted, collisions add an additional burden to the already energy constrained system. In this paper, we present an application-based approach to collision avoidance. We propose two specific algorithms; the first one follows TCP's congestion avoidance algorithm and adjusts the transmission rate when a collision occurs, while the second one shifts packet transmission times to minimize collisions. We evaluated both algorithms through simulations and our results show that our approach can reduce the number of collision-induced retransmissions by a factor of 8 and the energy consumption by up to 50%.