Eternal phoenix Fire said:
Also Maelstrom, it's been a while. Where have you been buddy? =D
Well, I retired from competitive Smash a while back. . .that's why I've been AWOL for a bit. Although, it seems like I'm getting back into it again, which is something I really shouldn't be doing.
King Malice, if you can combo the Marth you're playing against, by all means, do so. It's just that you should keep in mind (if you one day happen to face some uber-level Marth) that you can't juggle him since he can always f-air out of it. All the Marth has to do is DI away from Mario and properly time a f-air, and the combo's broken. It's basically a free alpha counter; no meter required. (random old-school reference)
As far as straight-out KO'ing Marth, that's. . .something of a hassle. When I play against Marths, I usually get my KOs from d-smash/sex kick, and edgeguarding. . .that's about it.
In terms of edgeguarding Marth, don't be afraid to edgeguard him because of the sword. Marth can f-air/side-b on the way back to deter you, and his up-b can be annoying to edgeguard, but this doesn't mean that his recovery is safe. If you can nail him with a fireball right as he starts his double jump, it'll neutralize it and stunt his recovery (fireball spike Cape style).
You can also try to fastfall a b-air into him, either away or into the stage (for a stage spike if he bounces off the wall), but be wary if he has good teching skills. You can also cape his up-b--just stand a bit away from the edge to cape the tip of the sword, and you'll be able to cape him. Usually, when a Marth up-b's, you'll notice that Marth's body remains below the edge, but his disjointed hitbox (sword) pops up above the edge--and that's what you should be caping.
Also--and Eggz, I need your help on this one--I'm not sure if the light-shield -> edgehog works on Marth with Mario. Basically, you're suppose to roll at the edge of the stage (so you're as close as possible) and light shield (press Z during the roll to make sure you're using the lightest shield possible) while angling the shield diagonally downwards towards the edge of the stage.
When Marth up-b's, it's *supposed* to knock you down into grabbing the edge--seeing this, the Marth can't sweetspot (because he'll be automatically edgehogged) so he can only recover onto the stage, where you can take advantage of the lag. It's not as effective with Mario as it is with Falcon, because it's harder for Mario to take advantage of the lag (possibly an edge-dashed grab into b-throw, or ledgehopped sex kick, but that's about it), but it's just another edgeguarding tactic to consider--provided it works with Mario, I can't remember.