Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

For your purposes, though well-intentioned, the advice to use "automatic everything" camera settings is not very helpful.

But you do realize there are two parts to your question - getting sharp images, and getting a background that is nicely out of focus.

Sharpest images are accomplished with lens openings that are 2-3 F-stops smaller than the widest opening. Aperture F-Stops are usually seen as the following - F2.0, F2.8, F4, F5.6, F8, etc. When reading from left to right, each stop in this list lets in 1/2 as much light as the previous. So F2.8 lets in 1/2 as much light as F2.0, and so on.

This is important for exposure equivalence. If your camera is set to take a good exposure at F4 and 1/1000 sec, if you decrease the opening to F5.6, in order to get the same exposure you would have to increase the shutter open time to 1/500 sec.

A characteristic of wider lens openings is a shallower depth of field - in other words, when focused on a subject, a wider opening will just show the subject in focus, with less in focus in front of and behind the subject. A smaller opening does the opposite - more foreground and background will be in the realm of acceptable focus, with the subject being critically sharp. This answers your second question, of how to blur your background.

There is a lot more to this than can be reasonably represented in a response to a question, so my suggestion is to look at your camera manual first - to become familiar with how to set your camera to Aperture Priority to be able to select the aperture that will give you what you are looking for, and to understand what is "too small" an aperture that would require too slow a shutter speed and could possibly result in blurry images - either from camera movement (shake) or subject movement (like a flower swaying in a breeze).

A really good place to really get going with this technical "stuff" might be a local camera club. You'll find accomplished photographers, complete newbies, and everything in between. Many clubs offer instructional sessions and mentoring to get photographers well-founded in everything from basic to advanced topics and techniques.