1) you can almost definitely find people who play at your school or nearby unless it's really small. i found a lot of cool guys to play with at my college.
2) getting over a hump is a hard thing to do. it requires a lot of smash introspection. there's a quote that i'm currently not in a position to find about improvement that comes down to basically:
when people hit a plateau at something they're good at, there are three things they do:
a) give up or resign themselves to not improving
b) shore up individual holes in their game, but ultimately stay on the plateau with a bigger bag of tricks
c) start looking at the game a different way and seeing why what they're doing isn't making them improve anymore.
what you want to do is c. ideally you'd record yourself and study the videos. in addition to finding bad habits, you need to think about how you approach the game. instead of saying, 'i need to pillar less because it's not working' you need to understand why, things like that. start focusing on the issues behind the losses, not the immediate results. think about why you throw moves out in the places you do, and what better players do in similar situations. just spend a lot of time thinking about how your approach to the game or to matchups can be improved.
practicing tech skill and stuff won't ever get you to a higher plateau, you'll do the same mediocre stuff with greater consistency. you need to understand how you think about the game and then improve your own thinking.
Taking risks in games and thinking about (not just noticing patterns, thinking about the ideas behind) what works and what doesn't is a great step, though.
for a simpler solution: what's your problem? if your tech skill is weak, play a lot of fox and get your fingers faster. if your spacing is weak, play a lot of jiggs and thinking about space and positioning. if your punishment game is lacking, play marth or sheik for a while, because their games are punishment-heavy. if you're too offensive, play on bigger stages and watch jman games. if you're too defensive (don't capitalize on openings and put your opponent in risky spots), play on smaller stages or play a pressure-heavy fox.
it's all about figuring out why exactly you aren't improving and rethinking your approach to that aspect of the game.