Hey thought I would write some more tips for e_alert and others newer to the scene.. i'm not a pro but i think this can help.
Hitconfirming / Combo-confirming
So basically.. whenever you do a move, if you're not sure that it's going to hit you *wait and watch* to see if it does. The instant you see it hit / miss / block you *think ahead* what to do.. remember that there is some serious lag between what happens in Melee and what you see and also lag between you deciding to do a move and the input reaching Melee (as it travels through your body, then through the controller = several frames).
So really you can't play purely reactionary, seeing what's "going on" because you're really just seeing "what happened"..
Ok, difference.
Non-hitconfirm, Fox, Final Destination:
Fox dashes, dash attacks.
You wait until the dash attack animation is over to decide your next move. The opponent has already teched away.
Hitconfirming, Fox, Final Destination:
Fox dashes, dash attacks.
As soon as you hit "A" your eyes are on the opponent, waiting to see if they are hit.
You observe the opponent getting hit.
You prepare your mind & muscles for an up-tilt to begin the instant dash-attack ends.
Being an experienced Fox player you know exactly or close to exactly how long this is.
You wait X frames until Fox is *almost* done with the recovery, then tap up-tilt.
You've comboed.
Combo-confirming is the same thing except you're getting hit.
With each hit you see what the hit was and prepare a reaction *before hitstun ends* (and you DI here too )
You then anticipate the opponent's next move by their spacing, animation, your hitstun, relative position, your ability to tech, their playstyle.
And you prepare to either jump, tech, flop, attack or Smash DI (if you can predict accurately.. I find this harder then SFIII parrying !)
You get hit MORE when you don't notice you're in a combo-able position and attempt to mash and use f-air without DIing away or such.
What hitconfirming boils down to is waiting for the hit then "confirming" the results and preparing your next action -- anticipating the animation times.
Really basic/noob/we've all done it example:
You think "**** if I could just down-air them I could do a shine to up-smash and win"
You attempt down-airing.
Marth dashdance grabs you. (train your awareness to know a grab happened before you see the throw)
Noob: Mash down-air
Smart: Begin DIing / time SmashDI
k so, if the Marth was noob he would up-throw you then wait until the throw before deciding to hit you.. but against a good player he'll up-tilt/f-smash/f-air/chaingrab the crap out of you. if he's smart though, he's hitconfirmed his throw and knows he can safely hit you with up-tilt -- meaning you need to NOT try to down-air him but get the hell out of there.
There's also the business of hitconfirming, seeing them shield and delaying your lag-cancel.. I'm out of touch with that, but it's how you avoid missing l-cancels even when you're *not sure* if the opponent shields or not -- you wait, see, prepare (l-cancel).
Hope this helps.