Whenever possible try to avoid bending and turning at the same time. It's always better to turn first and face what you are doing before bending.
When you need to lift and carry something, keep it as close to your body as possible. For example, a fifteen pound infant held close to you becomes 150 pounds on your low back when you reach away from your body to lift him or her from or into a car seat or crib. For lifting something or for placing it down, step closer and bend your knees to use the larger, stronger muscles of your legs.
Try not to hold your breath as you lift and carry. If you catch yourself doing so, just count out loud (very quietly is fine). As long as you're making some sound you're not holding your breath.