Huge improvement. Just shows you how setting the white balance can make an image look so much better. Often with consumer pictures taken on cheaper cameras with limited or no WB control you will see these issues with the overall WB being completely wrong, especially indoors. But outdoors can have issues too as in bright sunlight you can get a blue cast over everything, which washes out colours and mutes an images. WB is definitely one of the most important settings to always remember to adjust before starting to shoot in any new location.

ISO is a little trickier because it works in combination with the Lens you are using and the other current camera settings. ISO is a precursor to the old film days. ISO was the sensitivity of film to light. The higher the ISO, the more sensitive the film, and the more the film would capture from the same amount of light in a scene. The same is true for digital cameras and the ISO settings they offer. The higher you increase the ISO, the more sensitive the camera's sensor will become to light. The issue, as was also true for film, is that the more sensitive you make the sensor as the ISO rises, the more you will introduce noise and artifacts into the image quality. It is therefore a good idea to try and keep the ISO below 800, and for most images below 400 to get the sharpest and cleanest images. If you are finding you need to increase the ISO to gain enough sensitivity to capture an image then instead try to use a wider aperture to get more physical light into the camera, combined with a longer exposure. In lower light scenes this obviously requires image stabilization or even better a tripod. Higher ISO is the option when you don't have IS or a tripod to hand in low light, or you need to take images of moving subjects in low light where neither of these will work.