1. Number 1. Make Link left-handed!
2. Don't make items become obsolete as you progress through the game - such as the slingshot being made redundant by the bow, or it becoming too weak later on in the game to be of any use (perhaps allow for upgrades)
3. No items whose (almost) sole purpose is to allow you to complete a single task/temple/dungeon etc. - such as the dominion rod in
TP or the flute (or whatever it was) in
AoL- all items should be useful from the moment you get them to the end of the game.
4. No items that simply take the place of another - such as the longshot in
OoT - that should be an upgrade not a new item.
5. Final battle should incorporate the use of all your items - if possible in less conventional ways.
6. Sword can shoot 'energy' when full health, like old school zelda (not like
SS)
7. Completely open map (eg. not
SS)
8. More than 1 way to solve puzzles etc.
Possible unconventional ideas: 1. Can obtain (a) follower(s)/companion(s) that travel(s) with you and fight(s) alongside you.
2. Each dungeon could contain 2 items, one relatively easy to obtain item that is required to progress in the game and another more difficult to obtain item that is useful or allows access to otherwise unreachable locations etc.
3. Alternate ending/storyline depending on your actions.