Accuracy is everything just don't throw out an attack unless your 100% sure it will hit. If your not 100% and throw out a move make sure its spaced.
Don't Fsmash unless it's gonna kill or send them off stage. When Falcon is off stage he should not come back.
If Falcon UpB's when he is even with the stage. (He isn't high enough to go over your head.) Charge Fsmash the ledge so your sword is off the ledge a tiny bit (To cover that option) He won't be able to recover behind you either.(I always do that, it can't be beaten <3)
This match
https://www.youtube.com/watch?v=w3CYE-mleSE&feature=channel_video_title
1:34 u grab>Uthrow. It would have been better to Dthrow to for Falcon off stage. Always put your opponent in the worst position possible whenever possible.
1:36 you double jump for no reason and get knee'd....Double jumping is bad.
1:46 you should of grabbed ledge, or dash canceled>Fsmash
1:55 you are corner to the right. You try and retreat by getting on the top platform and get knee'd. Being on platforms are really bad and you weren't that cornered.
2:08 Falcon Uairs you twice and you use your 2nd jump. Try not to use your 2nd jump unless your really have to. Falcon tries to Ftilt you, but you airdodged. If that stupid Ftilt hit you, you might have died cause you already used your 2nd jump. Always save your jump.
GENERAL MARTH ADVICE
You should Dtilt approach more. It's really fast and hard to punish. If Falcon is about to grab ledge Dtilt him instead of Fsmash. It hits him at a better angle the Dtilt ruins Falcon. If you were playing a good Falcon and Fsmashed he could DI it. IDK I like Dtilt a lot better. You should mixup Fthrow and Dthrow, all throws are good. Use WD OoS it's reallllly good. WD OoS>Fsmash is amazing. You spotdodge a lot. You should Fair OoS more its really good. You also need to Dash Dance more. Throw>Dash Dance. See what they do, a lot of times they will shield or roll or spotdodge. If they spotdodge you should nair, the hitbox lasts really long so it's guranteed to catch them. If you Uthrow them on a platform of course just Utilt your *** off. If you know they are gonna shield (They always do) before you could get off the utilt. Just shield-breaker them. This is known as the No Ca$h special btw. What I do is Uthrow them on platform>Waveland>Grab. OR!!! Uthrow>Nair. The Nair will cover all of their options, rolling, missed tech, tech in place. Maybe everything except get up attack.
VS FALCO
You gotta get those grabs and make him your *****. at 0% Fthrow>Fthrow>Uthrow. You can Uthrow him to 28-31% then you have to Utilt but even that ***** him (Unless they don't DI it) If they don't DI it it's just a simple tech chase. I heard ligthsheilding is really good vs his shield pressure but haven't tried it. You can catch people a lot of times with Dthrow>Fsmash. or Dthrow>Jab reset. Or Dthrow>Ftilt.
I'm not gonna comment on Marth dittos cause...they are just silly. Just Fthrow>Fsmash. Uthrow>Utilt. Dash attack, fair, and Fsmash. If they are at like....40%+ you can Fthrow>Techchase. Always Fthrow>Dtilt incase they miss the tech. If they roll Forward you can WD>Fsmash or grab again. If they roll into you, you can just grab them again :D
VS FOX
Same stuff as Falco except he plays much more defensivly. Dash cancel>Dtilt is god here. You really have to know your spacing and how to dash dance well here. His Uthrow Uair on you is mean. So is Shine>Uthrow>Uair
That is the perfect Marth video critique and Marth guide. Goodnight SWF.