Software design -- The confussion of buzzwords

First, some background. I am not a software developer, nor have I the training or experience to be one. However, I do like computers and have developed a desire to play with computers more then the average joe. I have done coding in 8088 assembly, pascal on both apples and IBM's, and since have found perl as my language of choice.

Over the years, I have developed lots of fun throw-aways but only one application that grew to any considerable size (+1000 lines). Recently, I have began coding more often and have noticed one major roadblock to my development which has really begun surfacing since I have begun playying with OOP. That problem is my process of development. I lack very much structure to my design. I code and fix. Learning from books has taught me understanding of the languages, the control structures, data structures, importance of encapsulation etc... But somehow I have ( missed || been unable to find ) any good knowledge of design. Other then the buzzwords I find on the net and in the bookstores the closest thing I have learned about programing design methods has been limited to Top-Down, Bottom-up, and I briefly remember some book I read that explained flowcharting... (Cant remember the proper symbols though!).

The problem with coding then fixing is that many times you are half way through coding your program when you realize that the way you have designed code that doesnt work, or doesnt work well. Then you throw it all away and start again.

So I decided to do some searching to get an idea of the methods and processes used to develop software. There is so much information out there that you quickly get information blurr by the magnitude of buzzwords and design methods. Extreme Programming, RUP, UML, Use Cases, Data Patterns, Agile Software Development, etc....