I just need to remember to use the darn things, which I never do. Also, taking the 3DS out for walks, which I don't do too often. I keep it in a small computer bag, and it's just clumsy to carry that around, and my pants pockets are often too small for it.
In terms of teams, mine is going through gradual changes, with a few static members as I rotate some out to level others. Susan is my lowest level, currently, so I keep some leveled members on hand to help him out. Runaway has a nice type spread in his moves, which I may keep, while Mewtwo may see some move changes to see what type spreads work best.
Runaway's best stat is his Attack, so he's a somewhat physical Alakazam, though I lean more toward Special Attack for his moveset, while Mewtwo gets more physical attacks to exploit the additional Fighting typing when he Megas.
I keep two HM slaves on the team for exploration, travel, and capture purposes, though Pierce's moveset will soon see some changes as I work on providing him with a type spread.