Wall of text time, lol
scroll to bottom for cliffnotes
First and foremost, understand marth can defend himself on recovery (you probably know this which is why you're asking).
Now, understand that even on recovery, marth still outranges doc (technically speaking he doesnt, but I'm talking pills at that point, that's some later-on-down-the-road-kinda-stuff).This is important because that means Doc has to hit clean, there really wont be any trading involved.
When marth recovers, doc his has to be weary of getting f.aired (or really, any aerial, neutral b, counter; there's alot marth can do). But the thing is, he's only got one shot. There's enough lag that if he throws something out there and you're in the area, he's done.
With that being said, edgeguarding marth comes down to being outside of his range and going in either
A) After he tries to stop you and misses
or
B) If you think he's not going to try to stop you at all
You're not going to just casually float out there and b.air him unless you know for a fact he's not going to swing (And if you find a marth like that, please let me know. I would love to go do the superman edgeguard to him a few times for kicks.)
You have to do stuff like wavedash off, capestall out of his zone, ledgedrop a b.air, etc. He's not completely defenseless on recovery (and he's really not in TOO bad of a spot as long as he stays above stage level.
Once he goes below stage level, you're looking to edgehog. Dont try to fight him, just edgehog. If he's trying to recover low (read: low from real far otu), then instead of trying to down and b.air, just rain pills on him. 2 or 3, depending on how fast you got to the ledge, and then get on the edge. Make him up+b past you, punish from there.
Caping marth is hard. It's hard for 2 reasons.
1) he has to miss a sweetspot
2) YOU HAVE TO STAND A GOOD DISTANCE AWAY FROM THE LEDGE.
The problem with this is that it's kinda hard to get as far back as you need to in a timely manner to stay out of up+b's range, but close enough to cape.
.....*dogy gets more ideas*. I got some **** i'll write down and try sometime. XD
Last, if marth's recovering high, FOR THE LOVE OF GOD STAY IN FRONT OF HIM. Like, you dont want to overexert yourself to get him at this point (you MUST be in front of him, you CANT be below him), but for the love of god you've got to stay in front of him or get d.aired. That kinda thing can be devistating.
**
Now, with all that said, know that there are a few things to look for.
1) Look for marth to side-B too close to the stage.
- If you can call a side-b, hang out in the area and b.air him afterwards. You've got enough time.
-Same thing applies to any aerial
2) Just like basically every other character in the game, he's scared of getting b.aired. -but he can defend himself well-
- with that being said, if you can come up with ways to fake him and he gets scared, he's more likely to jump at you and f.air than drop down out of your range. It's safer for him to try to swat you away.
- And because people have put up with my walls of text for so long, here goes 2 random Dogy tips for... who knows how long (im going to keep typing this paragraph to deter people from reading lol. I a bad person). Both for edgeguarding. (for anybody who keeps up with my termonology, these are "smart tricks" (meaning your opponent actually has to be intelligent for it to work)) First one is if you ever want to entice somebody to jump (usually in a spot to waste a double jump), wavedash in place. Works if they're falling back to the stage, recovering, etc etc. Reason this works is because doc makes a sound every single solitary time he jumps, regardless of what he actually does. He even goes into the same jump startup for anybody who's actually looking at him. So if somebody is smart enough to know that "WAH" = jump, they're going to be more inclined to jump away than if you just stood there and waited for them. In all actuality, all you're doing is standing there waiting for them.
-Next thing is spinning on the stage. Alot of people understand that if you're back is to them, you can b.air them. Alot of people ASSUME that if you're facing them, you're going to throw pills at them or cape (or any other edgeguard if you do crazy stuff). Look at it like this, if your back is to them, they better go low (or high) or else they're going to get b.aired. They also should hurry up because you get bored and decide to take the ledge. If you're facing them, they better not go low unless they want to get rained on by pills. You start spinning on the ledge, and who knows what the f**k you really want to do? You'd be surprised that some people will jump if you turn around.
But yeah, another thing to keep in mind is what your opponents responses are to your edgeguarding options. It's good to know if your opponent will actually try to airdodge or not. If they will try it, you can catch some of those people by just simply standing there with your back turned. Same thing with stuff like counter (for marth specifically). If you know they'll try something like that, know that sometimes you just have to throw a pill out there and go take the ledge.
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CLIFFNOTES VERSION: DONT BE SO BLATENTLY F***ING OBVIOUS WHEN YOU JUMP OUT THERE OR YOU'RE GETTING BATTED AWAY.
