The Spanish international joined the Swans from Valencia last summer for a club-record fee of £5.5m.
"I don't think the record transfer fee has been a burden," Hernandez told Sky Sports News. "But it's possible to play better.
"Sometimes I play well and sometimes I play bad, but I always give 100%. But I think I can play well next season."
Hernandez has scored three goals in 30 appearances for Swansea this season.