Play against harder enemies. The ones that you are lucky to survive against. They provide the biggest boost for leveling up.
Look at it this way. Throw out the level indicators. If you have 50 experience points and a particular enemy was to give you 10 experience. that would be a big boost to your leveling goal. It would be a fifth of what you have already. If you survived against such an enemy, it would be plenty worth it.
If you faced the same enemy, and you already had 5000 experience points (EXP), then while you are getting the same amount again, the benefit wouldn't be the same. This time the 10 points is only a five hundredth of a boost. In the earlier example, going from 50-60 was a big deal in only one battle, but in the latter example, going from 5000 to 5010 is nothing.
Be careful and don't level up to much. You don't want to over-level and have the game be too much of a breeze. You should be fine. It has been years since I played the game. If I remember right, that's about where you should be. Maybe not too much higher. Remember, you want a challenge, but if you want to breeze through the game, than that's your prerogative.