The Marth match-up use to make me stay up at night, for fear of that stupid forward smash hitting me and killing me at 60%.. Ugh, the nightmares. But I’ve overcome that fear and now see it as probably my best match-up.
My keys to success against Marth involve a few different tactics and strategies.
1: First and foremost, if you are grabbed you must, MUST, DI it down so they can’t immediately f-smash you or get a good follow up. This is incredibly important as if you can reliably rest a missed grab and not get severely punished when you shield and are grabbed, your neutral game becomes infinitely better.
2: Whenever you are on the ground you should be crouching. This forces the Marth not to use grab and space their aerials better. If you do get hit by a poorly spaced aerial you then have the option to punish (usually with f-smash, up-smash, or grab). These first two points will apply pressure upon the Marth to respect you, which gives you the space and freedom to sneak in those wonderful back airs that you want.
3: Once your opponent finds out you can rest a grab or not get punished for it ever you have eliminated their ability to grab without some sort of set up or bait. SOOO now you have to learn how to bait a grab. There are several options here, instead of always falling with an aerial try just landing and crouch, OR, if you hit their shield with a well spaced aerial you can crouch next to their shield. Marth has horrible options out of shield and you can punish all of them if you figure out their habits.
Auto-cancelled nair is another option, where you place yourself within their grab range and crouch right after, they’ll go for a rest and boom, rest.
Hitting the missed grab rest is all about knowing when the Marth is likely to grab you. Its hard to do on reaction, but if you know they are likely to do it after you hit shield or are in landing “lag”, then crouch and prepare that down-B!
4: That forward smash isn’t so scary after all. Most Marth’s go for two types of f-smashes, wave-dash back f-smash and a read f-smash when they think you will land. So, you must not chase and over extend yourself against the Marth, instead, use those bairs to push them back into a poor position where they can’t f-smash. Then if they do f-smash you must punish. Second, a lot of Marth’s will try to f-smash you as you fall, so, fall and then jump right before that range and then you can punish.
5: How to move around. Wave dashing is your greatest friend here. Against Marth the worst position you can be in is in the air or on a platform, as that is where he can get his combos off and keep you at bay forever. This means that you should stay on the ground a lot, wavedashing backwards and forwards and occasionally jumping ONCE or TWICE (maybe three times) and throwing out some well spaced back airs and nairs. Another aspect of this idea is that Marth has the advantage when you come down. Therefore the object of combing back to the stage is to not get hit and make it safe, NOT to get a hit. So only try to throw out aerials to clear out space for yourself and to punish a very laggy move like f-smash.
6: This is the last point I will talk in depth about. Comboing Marth. Jiggz can combo the mess out of Marth, however, its not all guaranteed, kind of… Comboing Marth is all about getting him in the air, knowing how many guaranteed hits you can get, and then staying close and hitting him as soon as he throws out an aerial or jumps. You have to read their movement after a couple of aerials, don’t just throw and aerial out you know won’t hit, instead, wait a little and react. You can extend your combos a lot.
So there you go. Sorry for the long ass post but hopefully this helps. I have a lot to say about the match-up. The only thing I didn’t cover really is edge guarding, but that is really experience based and you can watch any hungrybox vs. marth player to see how to do it. Anyways, here is a video of me playing a decent Marth so you don’t think I’m full of it and maybe it could help.
video: youtube.com/watch?v=SKYigsCX6jw
Edit: left out www. for the link cause it won't let me post links for some reason