A little photography know-how can go a long way towards getting better pictures on your cell phone, especially in difficult lighting conditions.
Photographs are a way of capturing light, and to get a good photo you need to capture the right amount of light. A camera offers three different ways to adjust the amount of light that goes into a photo. First, you can adjust the aperture, which is the hole that the light comes in through. A bigger aperture (smaller f number) allows more light to shine through. Second, you can adjust the shutter speed. The longer the shutter stays open, the more light pours through it. Third, you can adjust the sensitivity of the sensor, which is measured by a number referred to as ISO (higher ISO means higher sensitivity). The higher the ISO, the less light the sensor needs to get a full exposure.
Each of these methods has tradeoffs. A wider aperture makes it harder to get a sharp focus on the intended subject, plus with the physical limitations of a cell phone a broader aperture only gets you so far. Lengthening the shutter speed means that any motion (in the subject or in the hands holding the phone) is going to cause blurring. And increasing the ISO causes a noisier, more speckled-looking picture, because the increased sensor sensitivity causes more pixels to "misfire."
Your phone adjusts all three of these automatically to try to get the exposure it thinks will be best. But for certain subjects (especially moving people!) in certain lighting conditions, it just doesn't give you the shot you want. Often it privileges lengthening the shutter speed over increasing the ISO. If you're trying to take pictures of your kid's birthday party at Chuck E. Cheese, you're going to end up with a blurry mess. But if you crank up the ISO, the shutter speed will be proportionately shorter, and you'll be able to capture your subject without excessive blurring. You might get a speckled picture with somewhat off colors, but at least you'll be able to see what's in the picture. If all you cared about was getting a snapshot for facebook, you've got it. And if the noisiness bothers you, you at least have a chance of fixing that in post-processing, which is no use against blurry pictures.
You can also use this same strategy the other way around to take better still shots. If you want to take a picture of, say, a vase full of flowers, and you've got plenty of light and steady hands, turn the ISO down low and let the shutter stay open longer. Because of the lower ISO, your picture will be cleaner and have truer colors.
If your stock camera app doesn't allow you to adjust these settings, you can find plenty of camera apps in the Play Store that do--Camera Zoom FX is a good one that's very popular. A cell phone camera is never going to match an SLR for photo quality, but knowing how to adjust the ISO will help you make the most of what it can do.