For programming you do need a plan and most of mine involve databases and php (or perl)
I usually am too lazy to write the create tables script as creating the tables and how they interact in phpMyAdmin usually helps me focus what I need.
I then write the connectors (and test they work)
I then write a script outline by comments of what I need in the way of functions
I then write the controller fro the functions a bit at a time, starting with checking usernames /pass and validating any user data etc.
I then fill in the blanks where the comments have noted I need a function.
Three things to remember: Test, test and test again!
If you test as it builds you will find it easier than trying to test whole scripts.
And remember echo is your friend
