What settings do I use to take good photos?
The reality is many people can make good photos without knowing a whole lot about photography, if the light is right and they have an eye for knowing what looks good. More often than not, getting a good image without understanding a few basics of photography is luck or like using a microwave. Sometimes the microwave food is pretty good, but its usual not that great.
Usually great food comes from an oven or a stove, but using these two appliances requires some thought, preparation, and some knowledge of physics. Using a camera is the same way; auto mode is like using a microwave. It will meter the light, survey the scene and guess at what you want. Many auto modes, especially those in the iPhone are getting pretty good. However, there are still many conditions where giving the camera a little more information about what you want to do will help it produce a nicer photo.
Yes, there are scene modes, and I use them regularly in a pinch. These give the camera more information about what you are trying to do such as photographing sports, scenery, or taking a portrait. An example of where these will fail you is putting the scene mode in say "Low Light." Sometimes this works well if your subject is still, but if your subject even blinks or moves in the slightest way, your shot will be blurry.
This is where an understanding of the photography triangle of Shutter Speed, Aperture, and ISO comes into play and can help you decide the optimum settings for the scene you are trying to capture. I know this sounds intimidating, but learning that concept will free you from having to rely on Auto and allow you to become really creative. So, if you really want to get better, take a class, watch some online videos on photography, or read a photography book. Many times you can find a book on the camera you own that will teach you about the camera and the basics of photography at the same time in simple laymen's terms. David Busch's books are great for this.
Furthermore, unless your planning on becoming a pro or getting super serious, you don't need to buy a DSLR. Why do I say that? Many times when you buy a DSLR you would assume the lens that comes with it would match the capability of the camera, but this is far from the truth. Most of the time the lenses you see attached to the entry level DSLR's at Best Buy and Costco are "slow and soft." What the heck is "slow and soft?" Slow means the apertures (like the Iris of your eye) don't open up wide so you have to use a "slow" shutter speed which can mean blurry photos for sports. Soft means the glass is not as clear and doesn't send sharp focused light to the camera sensor.
So, unless you want to invest in thousands of dollars for High Quality Glass (Lenses), and you don't mind a giant heavy camera tied you all the time, don't buy a DSLR. This doesn't mean you are totally off the hook financially. Good quality enthusiast cameras that have some of the manual controls, advanced sensors, and nicer quality built in lenses will still cost you between $300 and $1500. Most of the "enthusiast" cameras I use are between $400-$800. These cameras can all make amazing images that you will cherish and amaze your friends with, but be careful! Everyone thinks they are a pro after they get one good image and it's easy to fall into the trap of thinking you are better than you are.
So, the next time you see a photographer friend who consistently makes great photos don't ask them what settings they use, tell them they make nice photos and ask them how they learned.