Having outside support is a bit like having a spirit. You can't see them, but they lend you strength all the same. Send or receive 600 "Nice!" marks, and you'll feel strong too.
Starting to get used to competition? Then set your sights on winning 30 Battle Hub matches. Gotta give yourself a challenge if you want to get anywhere in life.
Kung fu is the result of ceaseless training. Do anything enough times, and you'll see results. So will you, once you fight in the Battle Hub 100 times.
An alternate form of combat, with an alternate path to victory. Get 20 wins in Avatar Battles. But don't obsess over the results. Let experience be your guide.
I've worked a few odd jobs during my travels, and they all helped me with my training. You should take up a part-time job during your World Tour, as well.
Something in the way while you're walking through the city? Here's an easy solution: send it flyin' with a Master Action! Mm-mm-mmm... It's the little pleasures in life.