If you don't have people to play, you're never going to get good enough to do well in any tournament at any smash game, period.
In melee, you can practice tech skill on a level 1, and that may get you good enough to beat noobs, but it won't cut it.
In Brawl you can practice your spacing against a level 9 cpu, but that won't teach anything about matchups.
the best I can say it, go to every tournament possible and play friendlies all day.
or get someone to pick you up for a smashfest. or drive there if you have a car. There is bound to be someone within an hour of you who plays smash.
otherwise, i'm sorry. People make this thread every week, there is no 'EASY' way to get good at smash. i've been training for 2 years, and I'm still barely making it out of pools in my local tournies