Firstly learn how to work with the database (MySQL, SQLite etc..) - cause they're best friends from now on.
When you got that in your hat, then read some articles about security, how to secure your queries, log in securtiy ( watch your input field maxchars and allowed chars and check the - XSS is a .. nasty thing :) ).

When you become skilled enough to know what is the code of another programmer is doing - and you see the flaws/brilliance in it - great!

Also you can try out some Frameworks ( Zend, Cake or maybe RoR (Ruby) or Django (Python) ).
Frrameworks have the leverage of having the foundation for your application (DB Abstraction, user managment/access rights (permissions) and various other neat classes (e.g. Zend's Flickr, Amazon etc. ).
I support frameworks (if they have a string community behind them) and not-so-complicated learning curve.

Another thing you could ask yourself: Do I need templates?
I've worked with few of them (Smarty, patTemplate and phpLib or its clone xTemplate (bTemplate) )- and they are helpful if you want your code seperated from the design.
If I had to recommend a templating engine to you I would go - phpLib (bTemplate, xTemplate).

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