Great info Sheila thx!

Some stuff I'd like to add:

Another thing that can SCREW with FOCUS is the AUTO-Focus(AF)-ASSIST lamp/light that some digital cameras project to aid in focusing! Especially in LOW LIGHT situations! I have mine ALWAYS set to off!

Also, cameras usually enable you to SAVE custom/favorite settings, so you can access them quickly when needed! Take advantage of this feature, so you don't have to fumble with them later!

Since all cams works somewhat differently, you need to check you specific owners manuals to find out about these options!

Here's a link to some good info, which explains some of this stuff:

advanced-digital-camera-settings