Have you looked a bit in the Ability tab that is right next to the normal Level Up tab? Because most of said abilities are usually god sends for defeating stronger enemies. If also you've never gone out of the town I'd suggest to do so, since there's the fruit tree to get permanent stat buffs, as well as there being, outside the second wall, of the most useful companions (in my opinion) since it comes with the ability to make you grow bigger as the battle goes on. For the weapons the ones I do use the most are the "broken sword"(that you get at game start) since it gives more xp, the "broken essence of growth"(which I believe you get the most in the fake dungeon(go straight from the entrance to the town) and the cathedral-like dungeon(the one on the far left of the map), and the size sword(which you can get by killing some of the enemies that hide inside the bushes.
And if you ever need more help, buy some growth multipliers and some size potions, they usually do help out a ton)