Critical Cooking
Occasionally, when cooking, you'll hear a special jingle, indicating a 'critical success'. This results in a dish with enhanced effects (e.g., more hearts, longer buff duration, higher potency). This is random but more likely during a Blood Moon.
Blood Moon Mechanics
The Blood Moon occurs periodically (roughly every 2 hours and 48 minutes of active gameplay) and revives all defeated enemies (except bosses). It's also a good time for critical cooking. Use it to farm monster parts from enemies you've already cleared.
Durability Transfer Glitch (Patched in later versions)
Note: This was a popular glitch in early versions of the game but has largely been patched. It involved transferring the durability of one weapon to another. If you're playing an unpatched version, research specific methods.
Selling Gems
While gems are useful for armor upgrades, selling them is a primary source of rupees. Diamonds are the most valuable. Consider selling excess gems you don't immediately need for upgrades.