We examine small cell deployment strategies in two- tier cellular networks. Specifically, we propose a joint interference and load deployment (JD) strategy, reflecting a realistic interference environment and traffic load. In this JD, the location of a small base station (s-BS) is sequentially decided in greedy manner by exploiting both the spatial user equipment (UE) distribution and the received signal strength indicator (RSSI). Furthermore, we propose a deterministic deployment (DD), which does not require this RSSI measurement. In DD, the deployed pattern of s-BSs is the same for each macro cell. System level simulation (SLS) results demonstrate that the proposed schemes yield a cell throughput gain of up to 61%, when the UEs are densely placed near a m-BS. Moreover, 5%-tile UE throughput and median UE throughput are improved by up to 134% and 76%, respectively, when UEs are densely distributed far from the m-BS. Furthermore, the SLS results provide intuition on between load and interference in the s-BS deployment as follows: 1) load is more important than interference in the macro edge region, 2) interference is more significant than load when the s-BS is deployed close to the m-BS.