Like I’ve said, Itachi’s strength is in his versatility, which comes in the form of having a myriad of strategies you can implement with him. These are some of the more effective ones I’ve noticed as well as some of the underutilized strategies that bring out his true potential.
Turtling 1
-U1, support strategy. This is the most often used and abused. The basic concept is to spam the fireball jutsu and use supports from a distance. Because of this, he is difficult to approach. If the strategy fails, Susanno is used to clear any gaps in health or to claim an easy victory.
Turtling 2
-U2 punishment strategy. Some players just side dash throwing projectiles or run around doing absolutely nothing but using supports. The basic concept is to punish a frustrated player who attempts to dash in by using his U2. It is probably the most frustrating of strategies, as the kunai prevent you from using your own jutsu and cancel your supports, but if you dash in you will be severely punished. Again, Susanno serves the same function.
Aggressive SB
-Aggressively take advantage of U1, U2 and U3. This is the one I most often use. The basic concept is to SB your opponent as much as possible. Until your gauge is at 1, you’ll want to play as if you are using one of the turtling strategies, or at least careful if you choose to fight as I sometimes do. Afterwards, this is done by using supports (I like to use Sasuke as my sole one for his team boost in U3’s damage and the speed of which the guage fills) or by using Itachi’s built in SB capabilities. His fireball and grab do this spectacularly, giving you many options. When using all of Itachi’s “gifts” with the support and dash strategy, as well as the dash stun into U3, not to mention your opponent being thrown off by the sudden shift in strategies, the opponent is often unable to read your next move. You can then punish with a U1, U2, or U3 after SB. You have to remember a lot and be flexible, but it is highly effective. Susanno is used strictly as a backup.
Aggressive but Careful
-This is my secondary strategy, usually when I get bored. These players take note of their opponent's status more than their own. They fight the entire game, but act cautious when necessary, such as when an opponent is obviously attempting a punish strategy or can use a U3. This strategy is viable for Itachi because just about everything he has is useful. By changing it up the opponent is unable to read you, and add in the fact that their mentality will be in the "spam" Itachi mode, you should be able to battle most players in this manner. Susanno will be more of a change up then spam.
Pure Susanno
-Some players I’ve noticed seem to intentionally have their health depleted to the minimum for Susanno. Then they spam his abilities and once he runs out they turtle, block, knj until they can awaken again. This strategy (though annoying and dangerous) can be very effective when you’re not expecting it.
Side-note: All of these strategies benefit from his tilt. Use only to escape an already activated support or jutsu, and attempted combos or grabs. You don't want to be hit by a well timed U2 or U3.
Please Check out my other Itachi guides as well:
Intro and MovesetStrategies Against