If you’re having problems with syntax, you could try an editor with syntax highlighting. Until you get the feel for a language, simple errors won’t just pop out at you.
The simplest form of debugging is just to insert some print statements. A more advanced (and extensible) way to do this would be to use the logging module from the std lib.
The interactive interpreter is a wonderful tool for working with python code, and IPython is a great improvement over the built-in REPL (Read Eval Print Loop).
If you actually want to step through your code, the python debugger is called pdb, which can be called from the command line, or embedded in your code.
If you’re used to a fully integrated IDE, I would recommend using Eclipse with pydev, and PyCharm has a great commercial offering, with autocomplete, quick access to docs, and numerous shortcuts, among many other interesting features.