Alright. I think I've got a feel for you after the first two vids.
Both of you had a strange playstyle. There were several times when your foe would be on the left side of the stage, and you would randomly SH and BAir to the right. This made little sense. The sporatic attacks at times even made it look like many of your actual strikes were more due to luck than intentional blows. I don't know how this came about, but many more experienced players will punish reckless play like this. And speaking of punish, there were plenty of times where it seemed Steel2nd's mistakes are what let you survive as long as you did.
First of all, I think your friend has a better grip of the basics than you do. There were several instances where Steel2nd reached the 100%+ range, which really shouldn't happen when you're playing as Marth. There were so many smashes that you didn't land that could have ended the game. And worse of all, you were punished for the worst of your mistakes. All in all, I think (when you were on top of your game) you did a good job racking up damage, but have a difficult time finishing your opponent. And that could also be a problem with the basics like spacing. You missed attacks, you were punished for not giving enough room, etc etc. I think if you watch Steel, you'll see how he used proper spacing to defeat you, particularly at 2:49 (first vid) where he downed you with 49%.
Considering how often you both used shields, I was amazed that I did not see more surprise Shield Breakers. Also, with what seems to be anticipated attacks (you dodged them afterall!), there were not as many Counters as I would have expected. Choice Counters would have easily thrown the match in your favor. Also, you really like to spam the Dancing Blade with the D-finish (for the multi-hits), but why not try and mix it up with the U-finish then follow with the UTilt? If the foe has higher damage, you could even Dancing Blade with the U-finish then follow up with a USmash to knock him way into the air. A few good FAirs and you could have him all the way to the edge and gimped to death.
Also, you can use the Dolphin Slash for punishing your foe for getting too close. I saw lots of shielding the Dancing Blade and such, and if you're close enough to grab, you're close enough to Dolphin Slash out of the shield. Doing this with high damage might even kill your opponent outright ... if nothing else will get him out of your face. Now granted, don't use this move unless you know you'll hit, because you can get punished if it misses.
Key points I want you to think on:
- More combos. Use the Forward-B to combo into tilts and smashes. Do something. Don't always let it be a single-strike-then-retreat scenario.
- Mix up your gameplay with a surprise Shield Breaker every now and then. If you get even one good Shield Breaker off when your opponent isn't expecting it, it can shatter their shield and give you a free KO. Beware overusing!
- Counter is a good way to reverse your fortunes. Beware overusing!
- Work on your basics! Your biggest problem is spacing and always dashing in. By improving your spacing, you'll get hit less often, be able to punish your foes more easily, and land more hits.
- Don't always dash in! Walking/running allows for a more varied assault and better reaction to whatever your foe throws at you. I'd save the dashes for when you need it.
- Don't attack in the opposite direction from your enemy. Vets will simply pound you for throwing out random attacks.
You're a moderate Marth player, but the basics are hindering you and keeping you from being a vet.
