I Still Shoot Film

Besides not focusing correctly, the main reason you would have blurry photos is from using a shutter speed that is too slow without a tripod. Using a flash certainly helps in low-light situations, because it allows you to up your shutter speed, but not everybody wants to use a flash all of the time. The thing with plastic cameras is that they are not really “walk and shoot” cameras. Most of them (not all) have a “B” or “T” function and 1/60 for shutter speed choices, and if you walk and shoot at 1/60 your photos will definitely be blurry. I recommend stopping to shoot and holding yourself very still. If you have enough light, it should make a huge difference. Or, use a tripod.