Hello! There are some tips:
1. Don't use stamina potions if it's not Monday (double experience from sweeping)
2. Don't draw Seals Scrolls after 1, but 10.
3. Group Skills - really useful, it's a great help to have them maxed out
4. Good combo from the start
5. Do Team Instances to get Ninja Tools, which will help you increase your power.
6. Upgrade your equipment as soon as possible - really useful and increase power