Here are some starting tips for ISS64. I plan to go into some more detail, but here are some starters. These tips are relative to difficulty level.
Almost any formation will work on level one. This level is characterized by an atrociously soft defense. Play a 3-3-4 and develop your shot. Practice 1 v. 1 with the keeper; this situation arises numerous times during level one. A good technique to master here for the later levels is the chip shot. When the keeper comes out, hold back and tap B. Most of the time, the shot will lob right over the keeper's outstretched hands and into the goal. Also learn how to get behind the keeper. Right before the goalie comes and dives, change your angle of attack and use the dash. On level one, you can literally walk the ball into the goal. Shoot, though, so you can estimate how hard the shot should be and at what angle you should shoot.
Domination isn't hard to come by on level 2, but you will face some new challenges. The most notable change is that defenders will occasionaly step up and front a charging player. Here is the prime moment to work on the passing game. Play a 3-4-3 with two strikers and a recessed center-forward. This formation gives you passing triangles everywhere on the pitch. Utilize the one-two(C right) and the delayed one-two. These strategies enable your team to have more possesion time with ball, under less pressure. When using the delayed one-two, throw in a lob intermittently to bewilder the defense.
Level 3 is the default setting in the game. This level is the first where there is actually a noticable difference in the opposition(for example, Brazil will pose more of a threat than Turkey.) I recommend playing a 4-3-3 with a sweeper, just for insurance. You still have all the passing options that you did with the 3-4-3, only now there is more emphesis on defense. By now, you should master the through ball(C up). This proves invaluable when you are in the attacking third; the through ball will give you more 1 v. 1's with the keeper. Another good tactic is the short cross. If your wing has the ball, bring it down the flank until you are halfway between the 18 yard line and the end line. Quickly direct the cursor in to the box and gently tap C left. If it goes right, your center striker will meet the ball for a header. In order to get these chances, make sure that both the outside halfbacks and fullbacks join in the attack.
Probably the biggest jump in the game is from level 3 to 4. Defenses will now pressure the ball incessantly, and you will find it harder to maintain control. The best formation here is the 3-5-2. Have the outside halfs run loose on the outside and feed crosses, both across the goal and deeper in the field. You'll be suprised how often the computer will let you play outside with the ball. When crossing long balls, curve the ball towards the direction of the attack. This allows the player receiving the pass the opportunity to advance the ball immediately. With the three middle halfbacks, have one press up and the other two play alongside each other. Use a zone press strategy to put constant pressure on the other team. With 5 halfbacks, you should be able to have two or three men on the ball at all times.
Alas, the final test has arrived. Here is where all the in-depth features of ISS 64 really pays dividends. Basically, this level plays as close to a real soccer match as any other game I've seen. Good teams(Brazil, Italy, Germany) should stick with the 3-5-2, but everyone else should convert to a 4-4-2. In the formation, stagger the strikers so one is closer to the halfbacks. This will help link the attack. Have the midfield go with two wings, an offensive and a defensive player. In the back, play the standard stopper/sweeper and two outside backs. If the oppposition has two great forwards though, try doing this: move two fullbacks up and assign them to mark the opposite strikers. Play a double sweeper with the other two fullbacks, just in case someone gets through. With marking, you never want the last line of defense to be on someone. The may not win every header, and then your caught off guard. Use a strategy of both zone press and counter attack(make all offense and all defence the other two). Have the outside halfbacks join the attack, but leave the fullbacks to stay at home. If you choose to be a pathetic team such as Greece or Turkey, play a 5-3-2. Do everything the same, but now you have an additional stopper in place of the defensive midfielder.