When conducting strength training, make sure you establish a good mind to muscle connection. In other words really focus and squeeze the muscle you are working, in a controlled fashion. For example, when doing a pushup really focus on squeezing your shoulder blades together on the way down. And on the way up focus on stretching your chest muscles out to get the max out of this great exercise.
Note: body weight strength exercises such as pushups, chin ups, dips and planks are a great way to improve overall strength and conditioning!