The Legend of Zelda: Oracle of Ages/Maple

You will encounter Maple the witch each time you kill 30 enemies, or 15 while wearing Maple's Ring (#16).

Meeting Maple
You can tell when Maple is coming because her music will play and you will see her shadow winding over the landscape before she finally appears on the screen.

When she does, watch her path and move in her way so that she crashes into you. Both of you will drop some of your items. Link will only drop hearts, bombs, Rupees, and other replaceable items; Maple drops these as well but will also drop Gasha Seeds, Potions, Rings, and even sometimes Pieces of Heart! After the crash, collect everything you can before Maple does. Head for Pieces of Heart first and foremost, then Rings, then Potions, and then Gasha Seeds. Then gather up whatever else is left.

Maple cannot steal your Rings, Potions, or Gasha Seeds. Any you see on the ground dropped out of her, not you. This means even if you do badly the only consequence is losing some Seeds and Rupees, which are easily replaceable. If you allow Maple to take enough of your Rupees (the other items may also count towards this), she will eventually upgrade to a vacuum-cleaner. Now instead of sweeping up the dropped items she hoovers them up instead. She can also move and collect items significantly faster than before. When you play a Linked Game she will upgrade her broom into a flying saucer which is even faster than the vacuum-cleaner.
 * If you collect more items than Maple she'll say "grr... why you... I'll remember this!"
 * If you both collect an even amount she'll say "Hm, not bad... but that's all you're getting today."
 * If you collect less than Maple she'll say "Hahaha! Now I have more items than before! See ya!"

Item priority
Maple has an item priority for all of the items she drops. The list is below.

Item Priority:
 * 1) Pieces of Heart
 * 2) Gasha seeds
 * 3) Magic potions
 * 4) Magic rings
 * 5) Item dropped by Link, with this priority:
 * 6) Bombs
 * 7) Mystical seeds
 * 8) Recovery hearts
 * 9) Red Rupees
 * 10) Green Rupees

Link never drops the first four items in the list.

Her priority for Gasha Seeds makes it easy to get Magic Potions/Rings, and if you need to heal, her priority for almost all of the items is before recovery hearts, so it's easy to get them.