I'm decent at the game, not that great, but not that bad either. I play a majority of characters, but if I had to pick one main, I'd pick Meta Knight. I can also play a pretty mean DK, Peach, and Lucina. Although, I'm not on that often (mainly on weekends and various holidays), and I also have a roaring passion towards League of Legends, often playing that with friends. I'd be happy to help you, but I'm not sure if I could do it as well as others.
tl:dr: I'd help, but use me as either a secondary mentor or a last resort.
EDIT 12/1/14: Also, if you want to pick up Meta Knight, and you want a bunch of resources, data, and other nice things, go look at my Data Dump Thread! (Shameless Promotion) The Data Thread has a bunch of percentages (Thanks to Claxus), and a bunch of nice tidbits I could find (Many of them found on Jackson's theory thread).
There's a little intro paragraph in which I talk about the general idea on how to play Meta Knight, so try to look at that, first.