when it comes to specifically your wall, my advice is to use your ranged move, but off beat. Essentially don't spam the move, but use the fireball, then pause for half a second, then do it again. That'll mess up people who jump and avoid, and also force them to block more and thus stay still. Little by little you'll get a way in. If anything, do an EX move to blast through their stuff and get in their face.
Personally I'm running into a wall that's basically a cap of my skill. I'm not really getting the combos from online tutorials, it's rough, and i've only got 5 characters i'm mediocre with and the rest i'm just terrible at. I can beat the computer, but not a decent player and it's a real bummer. So what I do is I play the best people I can find and just watch them kick my ass and switch up approaches. At the moment I'm using Jax, and on a huge losing streak (except when I get matched against some unlucky noob (talking about versus on the vita)). It's embarrassing but humbling at the same time. You learn your place, since it's not like you're supposed to have high stats if you have a low level of skill, and get more patient.