Cleaner images in low light
If you are shooting in low light and cannot use a flash, simply turn on steady shot and add a slight Exposure comp. Exposure compensation is better than increasing ISO because the former increases light to the sensor (so noise stays the same, signal goes up, better s/n) whereas the latter amplifies available signal (you add amplifier noise as well as amplify both the signal AND noise thus increasing overall noise). The steadyshot mitigates against handshake due to the slower shutter speed.
If you are shooting in low light and can use flash (or are shooting fast moving subjects – kids at a party -and need a faster shutter), use the popup flash, setting the Flash compensation at -3EV to -2EV, with auto ISO (ignore the steadyshot warning). In most conditions, (subject is more than about 2m away) this gives you the same light composition (as -3 to -2EV is barely noticeable unless it’s getting reflected on glass, and won't overpower existing shade and tone), but the camera will choose an ISO around 100-600, rather than 1600 AND select a much higher shutter speed, giving you really crisp images. In fact, I *always* use this technique indoors with the A77, even in bright light, and get really good results