Welcome to photography! There are many techniques to learn and features to explore and master. It's easy to feel overwhelmed by the vast number of techniques beginning photographers have to choose from, especially since the guiding principle is "do what you like best." The following paragraphs contain a number of insights you can apply.
Learning how to properly expose your photos is key to great looking photographs. You can properly adjust your settings by using the histogram feature of your camera. The histogram on your camera shows you what the exposure level for each picture will be and whether or not that is under or over exposed. This will allow you to adjust the exposure for the next picture.
Although you may want to have the camera set on the lowest possible setting so that you can have more images on your card before downloading them, you should ensure that you understand exactly how much print quality you're giving up. The only time to use lower settings is when you know the images will only be displayed on your computer screen.