Well seeing as you are almost done with the coding it will take alot longer to put into place good practices than doing it right the first time. Just remember the famous "//" marks if you comment everything it will be the best thing you can do for yourself and the help or anyone that uses the system. I would hope that you would be trying to distribute it freely if it is truly something great. But I would not help you unless you read so here is a great site for php information. and it should help you on your quest.

I hope you find what you are looking for and make sure next time you start the practices at the beginning or a variable change can cause a huge headache.