System Abstraction

Greetings, I'm in need of some development advice.

I'm working on a project which in itself is fairly simple and
straightforward, taking user data from the web and putting it into a
database. The data is handled in various ways and reports are generated
from the data. The project involves dealing with data from several
categories and I'm adding the code one category at a time.

Each of the categories are similar, but not exactly the same. The result
is I'm writing largely new code for each category. I've been able to
abstract some of the code, and I know it is possible to do more
abstraction but I'm hindered by lack of training. As I've added more and
more to the project the whole thing is starting to become somewhat
unmanageable.

What I'm looking for is recommended websites or books to help in the
design process. I've started a sub project to my work to try and
re-design the whole thing based on a more abstracted system. This will
cost me some time, but will be well worth it in the long run if I can
come up with a method.

What are some good sources of information on planning and implementing
abstraction (also interested in templates) for a website? I'm interested
in design concepts but also in code examples for how to pull off some of
the concepts.

Thanks,
Chris

--
Christianity has not been tried and found wanting
It has been found difficult and left untried.
- G. K. Chesterton

http://www.musterion.net/