U can get ur pkmn higher lvls by training them ur puttin them in the daycare center
BORING im sik of that now this hint is pretty surprising

pkmn seem 2 gain more experience if u dont let them evolve (press B while theyre eveolving) well not more but they wont need as much sure it will lower their stats a lil but its worth it lose the battle? go bak and if u keep losing u will still get exp. 4 the pkmn u beat so keep goin and ull get higher then evolve at like lvl 40 or sumthin and u will notice a huge change