There is quite a lot difference between structured programming and object oriented programming. In structured programming , you concentrate on the things to do . You than devide the whole thing into a number of procedures (functions in C) the data is a subsidary thing and is just use to pass information between the procedures. In object oriented , the data gets important . You define objects which actually represent data related with some thing or concept and you put the procedures that act on those data along with that ) . Mostly data is only accessible through those procedures ( functions in C , methods in Java ) . Object oriented makes the designing easier and it also helps to make the program flexible and clean. Object oriented is just a way of designing , you can do it in any language , even in assembly :-) . You can do object oriented in C using function pointers and structures. If you are new to programming I'll advise you to go for C++ and learn object oriented design , this will help you in long run. As for which programs to make , try thinking of what you want your computer to do , and try to see whether you can program such thing. Like for example for starters , you might want to create an application that stores the phone numbers and addresses of all your friends.
And remember programming is great fun , and is one of three things , every one on this planet should know.