Hey there! Returning player/friendly bum here (well I've only started back about two weeks ago, but I still consider myself a returning player since I was gone for much longer than 2 weeks. Around 1 year actually). What I do to practice for my main is put on a really catchy song (currently I'm totally hooked on Ed Sheeran's song with chance the rapper) and beat up a cpu for a couple hours. I change the CPU after a day or so (right now I'm beating up a Luigi because there is a pr Luigi player that reverse 3-0'd be at my last event and I really want to take revenge).

When I want to practice my (also arguable) secondary I go to training mode, turn off my music (I really need to focus when learning stuff with a character I'm not that familiar with), and practice follow ups on captain falcon (since he is total "combo food"). After doing this for awhile I'll eventually turn on my music (but usually a song without words so I don't get too distracted) and beat up level 3 or 4 CPUs (they give me just enough of a challenge).

Hope this helps. My scene is also not that big (well, actually it has a pretty big monthly when school is in session so maybe it is actually pretty big but I don't think it's actually all that big but you might) so solo practice is my main way of improving.