There are a lot of selections available when you go to post something in Google+, but all you really need is "public". I experimented with Circles, but found all of the limited posting options annoying. I don't want to limit the people who see my posts!
If you don't see "public", click the x on whatever box is showing (it might say limited, or whatever) and then select public.
The good news is that after you do this once, you never have to go back and change it.