You guys just gave super specific examples when you should have gave him a guide so he has better knowledge on this subject.
Like this:
Building and Sustaining Momentum
Need Help with Intelligent Aggression
by Cunning Kitsune
I have actually recently been addressing this very issue within my own gameplay. Perhaps I may impart a few words of wisdom.
First off, the key to "intelligent aggression" in my eyes is the ability to create, build, and sustain one's momentum. While a rather abstract concept, momentum can best be envisioned as possessing control of a match and dictating the movement and flow of that match (as I stated, not the most concrete of definitions, really). A significant portion of this relies upon your ability both to read and to react to your opponent. Successfully anticipating your foe will allow you both to stay on top of him or her and to punish any openings. However, this approach requires a good deal of thought, instinct, and proper decisions on your part, all components of higher level play (to which "intelligent aggression" is a gateway, in my opinion).
What you are looking for is the ability to read, predict, and punish your opponents, which ties back in to the concept of momentum discussed above. The most I can tell you here is constantly to look for some of the most common openings in an opponent's game. As well, while on the offense, keep a sharp eye out for some of the most common efforts by your enemy to gain some breathing room. You should notice that all of these scenarios imply that you are on the offense, pursuing and attacking your opponent, while they are trying to find an answer to your aggression. One of the keys to "intelligent aggression," is the ability to find answers on the fly to your opponent's efforts to escape you; this will allow you to stay on top of them, to maintain your momentum, and to play intelligently while staying on the offense.
Technical aptitude is also very much required for a successful offensive game plan. If one wishes to maintain his or her momentum (and thus his or her smart, offensive play), one cannot afford to lose all momentum instantly by getting shield-grabbed, out-spaced while approaching, grabbed from a falling aerial without an L-cancel, etc. You will notice that in all of these scenarios, were the player to have complete technical control over his or her character, he or she would emerge unscathed thus maintaining control of the match (momentum) and protecting the integrity of the offense.
In short, then, the keys to a successful (read: smart) offense are both mental and technical aptitude. However, there is one more ingredient to the mix, and that is your own absence of fear. You can never allow yourself to become afraid of your enemy, or that you might get punished if you go in, or what have you. Sometimes you just have to go in there and take what you can get. If you connect, keep your momentum and stay on top of your foe, always on the look-out for those easy openings and attempts to gain some breathing room, and following (key word) as appropriate. If you miss and are punished, DI the upcoming hit or hits, make the proper teching and recovery decisions, and keep on going. No fear.
My note: Playing Smash for the last year has taught me to think in terms of frames not seconds, this is one of the biggest differences to any other fighting game in my opinion, 6 frames(1/10th of a second) can mean the difference between winning and losing a match. A seconds hesitation is Smash is a lot longer than in most other games.
King Kong - "Do you think the same theory can be applied to a defensive playstyle?"
Now, regarding your question, I do believe that the same theory overall can be applied to a defensive game; however, some slight modifications have to be made. For instance, instead of reading for attempts to escape, you instead would have to read for opposing attempts to approach. You would have to look for when and how your foe would choose to advance and counter accordingly
You would also need to anticipate what your more aggressive opponent will expect you to do and then react contrary to his expectations (here is where having the ability to switch between play styles is especially useful). In effect, you need to be able to reverse-engineer your opponent's mentalities while playing defensively; note, however, that this same concept can also be applied to the aggressive styles and, indeed, any instance of the mental game at all.