Well I can help you with a couple of things. First of all you can download my
Dick O'Kane Technique practice mission. No, you're not leaning the Dick O'Kane technique, that's for later, but this puts you in the warm, safe waters around Catalina island off the peaceful coast of California with just one target, no bad DDs anywhere to be found. You can practice stalking him to your heart's content!
Now you need to look at my
Auto Targeting Training Video, the first of its kind, since nobody thought it was necessary. You and a dozen other guys say this video is necessary and it shows you all you have to do to put a torpedo in the side of your target.
Once you get feeling comfortable with driving the boat into position and letting loose automatically targeted torpedoes on your hapless foe, you can visit the
Sub Skippers' Bag of Tricks thread, where there are all kinds of begginers' and not so beginners' manual targeting techniques you can learn. Have fun!