SS1s usually play defense. Sticking with the team, using their sonar to keep enemy subs away from friendly BBs. 

Best to wait and let the enemy come to you. Once you get to SS3 and higher, then you can go on offense. 

If you're still around during the mid to late parts of the game ~ The other team might not suspect you coming.  As with any lower tier ship, it's about taking advantage of the situation which usually involves watching and waiting.

I've played KM SS1 and SS2, I've found that you have to be defensive and try deal with enemy subs first. You can do this by looking at what direction a enemy sub is going, and positioning yourself to intercept that sub. Or by just following a fellow BB, and waiting for enemy subs.
  The only time you have a reason to go on the offenceive is in the late game, when the enemy team starts rushing toward your team mates. In this sitution try to go for damaged BBs, and only fire fast torps at the shortest distance possible.
  Thats my experiences, hope you like submarines :3.

-Occult 

Here you go.....I wrote this for the forum some years back: 

As soon as a USN player gets a Bridge Operator to SS1 Level, he piles into the O Class sub.  He heads to his first Great Battle room ready to sink enemy BB’s.   As soon as the first game starts, it like “What the Heck”???    The sub is slow.   Really  S…L…O…W.   Never mind, charge across No Mans Land and Sink BBs!!      Ooops….can’t……quite……get….there.     Not enough air and KABOOM, a hail of Hedgehogs, a basket of Depth Charges, followed by a rain of Shells and the first game ends with a trip to the bottom.    Repeat this a few times and it begins to dawn that this SS is not at all like one imagines.    Is this a turkey or what?

Not really.    Playing an O class SS takes a different mindset then Blitzroom charges.   The O class sub is an entirely different critter and it must be played differently.     How is it different and how do you play it different??     Let’s see what an O class SS really is.

HISTORY

The US, and for that matter, the world’s navies, thought little about submarines prior to the First World War.  Generally accepted naval thinking did not have any great roles for submarines except for harbor and costal defense.     In spring of 1912, a young officer by the name of Nimitz (Yes, it was Chester W. Nimitz) presented a paper at the Naval War college in Newport, Rhode Island on the subject of defensive and offensive tactics for submarines.    Nimitz foresaw the development of a “Fleet type” submarine capable of the same cruising range as a battleship.    However, this couldn’t be done with the present boats.   The present boats were gasoline powered and had very limited range.    A submerged boat would fill with crippling fumes that could result in a disastrous explosion.    Nimitz predicted that the future development of the submarine would make it a “most dangerous offensive weapon”.    Nimitz was also the Navy’s leading diesel engine expert and within a few years, the US was installing Diesel engines in submarines.    Even with diesel engines, tactical thinking still considered the submarine as a harbor and costal defense weapon.   One thought was to put a fifty foot tall radio mast on the boat so it could warn Battleships in harbor of an attack.  The mast could be taken down and the sub could dive in about five minutes.  A far cry from the crash drives of WWII.    It would not be until after World War I would the US Navy build the S class Submarine which was the first step towards the “Fleet type”  offensive submarine.  The S class boat would see action in WWII.  &

Hi! I dont read last wall text (probably what I will say its on there)

first. learn your torp range, both, range with slow speed and range with fast speed.

Go to test room and play to sunk BB only with splash hits. When practice come high you learn to calculate ur fires to be in the place must be to sunk an enemy ship (truly u want to sunk that ASW little ship that chase u!)

Second: u must learn to use SS "triangle". Ur nose (or tail) is one point in triangle. Other point is where enemy ship is at fire torp moment, last point is impact zone (where enemy ship will be). That is very important for low level subs, to fight defensively, using reach and calculate skill to counteract direct hit and speed ships that you find in enemy subs SS4+ and ASW ships. This trigonometric aspect of submarine war (in RL too) is frecuently underestimated.

Third: Crew. dont let sonarman & planesman get behind in level just because his effects in ship at low levels are cuasi-irrelevant, you really need them at medium and high levels.

4th: Learn about training sub crews, is much different to train a BB crew that to train a sonarman or a BO for subs.

Surely others players say to you that "train in CL or CA till SS3 or SS4 level!" is true in some sense, but if you dont learn some things in low levels is difficult to say if you REALLY ARE A SUB DRIVER.

I hope u can reach SS 5 soon!! :)