Hey nice work!!! What's your approach against Marth? I hate to match up against Marth with Mario.
Well with Mario it's always a hard matchup against Marth due to range. You really can't space against him with projectiles cause his sword can easily eat them away. What I suggest against a good marth player is try to get on the inside and stay low to the ground. If you're on the outside you have to space him till you can get on the inside (bait him to do a shuffle FAir or something for a shield grab). Down throw is your friend when you get on the inside with him. You want to cap as much damage as you can when you get on the inside also, cause you do not get alot of chances due to range and prority. You can combo Marth pretty easy with the UAir Blind cause of his overall weight, and a well placed NAir at the end of the combo sets him up for your strongest positioning against him, edgehogging. You can cape Marth pretty easily or BAir him if he's mid-to-low postioning off the stage. If he's @ higher positioning, then your mindgames will have to come into play. Try various attacks or baiting (pressuring your opponent to attack you and then you counter it) him. Different people react different ways, finding which way works for each Marth will not be the same with another.
Like many things this is only one stratedgy, and your opponent can change up, but the main idea is still there, get on the inside, cap as much damage as you can while staying on the inside, try to set up for a Up Air Blind and edgehog ur butt off. Hope that helps ^_^b