This page covers general Hokuto no Ken strategy not specific to any particular character. Refer to the Characters section for more in-depth information.
Boost on the Attack
Aside from its use in combos, Boost is also a very potent tool on the attack, and allows for extremely fast and hard-to-see offensive maneuvers. Having a bar of boost stocked and ready gives you the ability to instantly close the distance between your opponent and punish their mistakes, even from long range. Apart from obvious spots like when your opponent misses with a move that has long recovery like most characters' far C/D or a Grave Shoot, Boost-attacking an opponent in Landing Recovery can also score you a guaranteed hit if timed correctly. Landing Recovery is the time where the opponent in unable to act after performing an air move and then landing, and most air moves have Landing Recovery, with a few notable exceptions like Raoh's air C and Toki's teleport.
Boosting an air dash along with an attack allows for a very fast and long ranged overhead that can be hard to predict, especially as opponents will often focus more on the danger of a Boost low attack when they see you have meter. It is even possible to do a cross-up from as far as half screen away against a crouching opponent - a useful way to accomplish this is by first performing a low attack like 2B at a distance, then instantly Boost air dashing.
Another very deadly use of Boost on the attack is Cancel Boosting an overhead normal(6A for most characters) into a low like 2B. The low attack comes out so fast that it can be hard to guard even if your opponent knows that you are going to do it - done in the middle of a mixup against an unsuspecting opponent, it can seem impossible to guard. The only downside to this maneuver is the large amount of Boost required, as most characters will want to have at least 1.5 Boost in order to follow up with a full combo. Facing this move, the best way to deal with it if you can see it coming is to jump and Aura Guard.
A slightly gimmicky but still very useful use of Boost is Boosting the startup of an air special move when very low to the ground, which causes the animation and sound to play, but you land and recover before it actually executes. This is used as a feint, and is usually followed by a throw - the first time you do this to an opponent it is pretty much safe to say they will never see it coming. It is important not to use this technique often however, as it can be very easy to deal with if your opponent knows you are going to do it. Two characters with very practical uses of this are Rei with his barrier and Kenshiro with his Shichishiki Heizan.
Boost on the Defense
Boost has a few defensive uses, the most common of such being Boosting a move you missed with to prevent being punished. This can be done as either a Movement Boost, as in the case of a missed reversal dragon punch, or a Cancel Boost, such as when your opponent Agility Defends your Banishing Strike. In the former case, it is often best to delay or even not Boost your uppercut, as most intermediate players will assume you are going to try to Movement Boost - sometimes you can even get lucky and avoid punishment by simply doing nothing if your opponent blindly tries to get into position to deal with your Movement Boost before you actually do it.
Another defensive use of Boost involves Kenshiro and Raoh's Musou Tensei move. It is actually possible to Movement Boost a successful Musou Tensei, which causes you to teleport a fairly large distance - when in the corner and under pressure this can allow you to distance yourself from your opponent. This is most useful when you Musou a move that you cant punish, like a 2A or 2B for example. Facing a Kenshiro or Raoh user, it is also possible for you to Boost yourself and escape after your opponent uses Musou on one of your moves.
Boost Management
As Boost plays such a critical role both offensively and defensively, learning when and when not to use it is very important. While it is often tempting to use your Boost as soon as you fill up a stock, in most cases it best to wait for a good spot - just having one or more stock of Boost to spare is a big advantage as your opponent is forced to play very cautiously. For many characters, 1.2 Boost is the 'magic number,' as it allows for a hit confirm Movement Boost while still leaving a full Boost stock to use in the follow-up combo. Boost management is doubly important for the weaker characters. For example, a Jagi user with 0.8 Boost may actually opt to not use the follow-up boost when connecting with a Banishing Strike, as a 50% Banishing combo is often not worth using his hard-earned Boost.
Another side of Boost management comes into play when deciding the best way to finish off your opponent during a Basuke combo. It is possible to drag the combo out and go for max Boost yourself, but this will often give your opponent a decent amount of meter as well. To avoid this, it may be best in some situations to strategically Boost at a certain point to prevent your opponent from gaining too much meter. There are also alternate methods of reducing your opponents Boost gain during a combo, such a through the use of a Grave Shoot, or special techniques like Traveling.
Imperfect Attack Strings
Many attack strings in Hokuto no Ken that connect normally in a combo are not in fact continuous strings when used against a blocking opponent. This occurs most commonly when switching from a light attack to a strong attack. It is very important to keep this in mind as it is possible for the blocking player to use Agility Defense or squeeze in an invulnerable move in these spots. Common examples of strings like this are Toki's 2A > 2D, Raoh's 2B > f.D, and Rei's 2B > 2D. When on the offensive you should always try to avoid repetitive use of the same attack patterns, as a thinking player will quickly catch on and exploit the holes in your attack string. Similarly, when defending you want to be able to recognize and take advantage of the weak points in your opponents offense.
A small amount of practice at this will likely show a great increase in your win rate, especially against weaker Toki and Rei users who are often prone to using the same strings over and over.