Ok... before you get into this wall of text let me say this:
I tried to come up with a helpful and informative post but the more I type the more I think it sucks and doesn't give you the answer you're looking for because to be honest... the answer you're looking for doesn't exist.
There is no "this is how I beat Marth so just copy it, do it, and you'll win" kind of answer
So just read on and hopefully you'll find something useful.
I spent about 20min writing this up because I wasn't sure how to get across what I really wanted to say and I've given up on making it better so just get what you can out of this...
and good luck on the Marf match up
Post begins:
Yo... Marf is a hard match up... not his hardest though... that would be Sheik but that's another story
Basically here's what's going on
Why marth is good against Doc:
- Most of Marth's moves outrange almost all of Doc's moves
- Marth has an easy time to grab doc
- Easy edgeguards on Doc
Those are the basic reasons why Marth beats doc
There are two solutions:
1. Pick up Sheik
2. Get good at the match up
So how do you do #2?
Honestly... I can't tell you what to do. There is nothing that you can find or I can say to start beating marth.
If there's one thing I learned from playing Smash these past two years it's this: Everything you read and learn from the forums will never make you better. You will never get better by reading these boards.
So why read these forums?
To gain knowledge. After that it's up to you how to use it.
I suggest to go back and read the Marth match up post and instead of reading it with the mindset of "this is how you beat Marth" read it as "these are tools that I can use to beat Marth".
For example, shielding Marth's f-smash > wavedash towards Marth > grab is a great tool to help you win the neutral.
Here's another one: forward wavedash > ftilt is another great one because f-tilt is one of the few moves that contests Marth's spacing
But these tools will never win you the game. These are options available to you and not a "I win" button.
Once you learn your options, practice them. Then implement them into your play style.
For me, I know that I have a defensive reaction based play style. What I do when I play Marth is I move around and try to bait out attacks or I try to move around his attacks and then when I think I found a chance to go in or I find a chance to punish, I go in.
I know all my options and all my tools to play against Marth and I utilize them.
Saying things like "I can't help but feel like the match up is near impossible" is never going to get you anywhere.
It's a hard match up. I know this very well since my practice partner during my first year of competitive smash was a Marth main. And guess what, I lost almost every game, but every game I would get closer and closer to beating him until eventually our matches were even. Yes it was frustrating as hell. I would even tell him. But I knew that one day I'm going to leave the Utah scene and go back to SoCal where there are tons of Marth mains.
When I played in my first big tourney, which was KoC4, I played against 3 Marth mains in my pool. I beat two of them. One of them was from luck though.
Now I'm not afraid of the Marth match up anymore because I know my options, I know how to get around his attacks, I know how and when to punish him, and I know how to edge guard him. But it in order to get to this point I lost to Marth so much that I lost count.
In order for you to get to this point, who you need to learn these options your self and implement them.
What I'm trying to say here is this:
Don't get discouraged... keep going. It's tough I know but the more you lose the more you learn and eventually you will beat your friend. Then you go play other Marth's in tourney and you will lose to them... but you will learn and eventually beat them.
Here's an old video of me when I was learning the Marth match up... it might help:
https://www.youtube.com/watch?v=X_KQPIOegB0
Edit:
Lol I just watched the video... man I was so bad XD but I did a few cool things... notice how at the end I was so flustered and how I noticed how bad I was doing XD