>Go to Hetare's Dungeon first thing
Sure, if you want to be a hetare. This is about the worst advice you could give since while the game is a bit hard in the first two chapters, all challenge is gone after that. The enemies just can't keep up with you, especially if you stack certain key skills such as Charm (turn delay) on different characters. If you do so, enemies will hardly ever get a chance to attack. Even then, you just start one and two-shotting everything (and it's really anticlimactic when you have no troubles dealing with story events). Once arena is available in Chapter 3, you could very effortlessly get infinite GP and in this way making the game much easier by upgrading every skill to level 5, stacking on action/HP recovery items, party buff items, etc.
What I would recommend is spending some time to create good Auto settings. It reminded me a little of the tactics system in older CRPGs like Dragon Age: Origins.