Remington has it right with the 'ask your partner' thing. All women (and men) are different and have different things they like. There are no magic tricks you can learn that will make you a good lover in the eyes of all women.
However, as an example of how there can be more than just 'in and out', I love the 'motionless thing', but very few guys seem to know about this technique! Basically, go as deep as she prefers (or if you're shorter, as deep as you can reach), then hold it there. For me it is best done right after I orgasm and will probably set off another. (Remember that this is only an example of something
I enjoy. It will not necessarily be enjoyed by all or even most of the women you will sleep with in the future.)
When it comes to different positions, speeds and depths, it's not as simple as changing things up randomly. If you want to be a good lover, you need to be able to read her in order to know when and what changes to make, and when to keep going. There's nothing more frustrating than someone changing what he's doing right when I'm about to cum. Make sure you put some effort into learning your partner's body language, and remember what things worked for future sessions.
You also need to remember that technique isn't just about the penis. There's so much more to good sex than just the penis, and this is often what women mean when they say that size isn't that important.
You may find this thread helpful:
http://www.lpsg.org/251923-ladies-sex-guides.html
