I wanna prove you wrong on this.
Whilst wearing that grin in your profile picture. I'd love it.
Anyway, everybody's said everything I can think of. Get a controller and scheme that's going to
work for you. Most people are going to tell you to get a GC controller, and I would agree (since it's what I'm used to, and what most people will refer to in terms of controls and terminology).
The first thing I'd probably do when starting the game, is find a
playstyle that you like above all else. Play around with the cast members, get comfortable with what you like. I loved Link, I loved the LoZ series, and when I first played him, Link was
very uncomfortable because I didn't know any of the technical stuff. So, I got into Mario. I figured out the tricks and quirks of the game, I figured out how to play on a slightly higher level, and with that, I was able to get back into the character I wanted to play all along. So, just because something feels weird, don't worry about it.
After you've got a playstyle figured out and a preference built, I'd probably focus on the fundamental techniques in the game. These include L-cancelling like people have mentioned, but having the Jab Cancel and Waveland aren't bad to get under your belt early on, either. Once your game speeds up and you
experience that rising level of play, you'll
appreciate it more and strive for a better overall game. It's like what was said earlier; my household and I started off at a poor level, but when we started investing time into it, people started asking "how did you do
that", and we'd tell eachother our discoveries, and take advantage of them and build our game up off of one another.
The biggest tip
I can offer, is to spend plenty of time in the metagame. Spend time out of the game reading, watching progames, studying hitboxes, collecting information off of the smash wikis and whatnot. Do your homework. When you've practiced hard all day long, the best thing you can do for yourself is to sit down and
read for a good long while. Watching Hylian do all of the janky Glide Tossing that he did against DSF made my jaw drop every time, and I watched that game
religiously; I must've watched it for at least ten hours worth of time. It wasn't until I started reading up on what he was doing that I was able to pick it out when he was doing it at lightning speed, and before long, perform it myself.
Nothing's more rewarding than having that
one trick that you just
can't do after hours of practice, and then reading and watching and
finally being able to do it every time on cue. Being able to do the Wave Dash was the first 'breakthrough' I had for my game, and it felt amazing, what a rush. Then, after a few months of not trying it, getting the DACUS down made me feel like I was only getting better and better. It feels good to improve, and you'll know when you are.
