Have a some items that you keep track of - provisions, money, arrows are all items that you can get more of, so instead of giving out some different item, you could hand out gold, food or ammo. There are other items that you can keep track of as long as you state their use in the intro. For example, you could have healing potions that restore 1 skill and 6 stamina points and have several vials of those lying around. Other such items include black cubes from Daggers of Darkness, spell gems from Scorpion Swamp, and magic rings from Legend of Zagor.
Get rid of unnecessary items: Have a gem worth 10gp? Why not just have 10gp? OR if you really want gems because gems are cool say 'You find 10gp worth of gems. Add them to your money.'. What about some healing herbs that restore 4 stamina points? Why not have another provision. Streamline the equipment you can get without reducing the flavour too much.
Have an inventory limit - stops clutter, is more realistic and it can open up some interesting game choices. How realistic you want to be is up to you. Lone Wolf has a good balance between realism and simplicity. Or you could just have a 5 item limit or a 10 item limit or whatever.
Make most of the items consumable - if they are a magic item, you lose it after you use it, for example a potion or a one use scroll. To make sure that people don't hang onto it, you could make it so that you have to use the item at a certain point.
Have the character lose some/all of their items - burglary, robbery, letting them go to prevent drowning - there are many ways you can deprive a player of their items. Use sparingly as it may annoy players if done too much.
Make sure items have several uses: For example, the pocket myriad from Citadel of Chaos can get you out of several scrapes as can the ring of fire from City of Thieves.
|I'm going on an epic quest|
and all you give me is two
meals and some advice?
Have fewer red herrings: Red herrings can be cool if you make players work for them. They are just annoying if they are a 1gp item on a shop list. Get rid of them.
Have shops in places where you know that the player can't afford everything: I love shops because it opens up choices but having shops where you can buy everything is no fun. Limit the player's spending power and they have more choices and shorter equipment lists.
Have items that are smaller parts of a larger item: Collect the components for a magic item and you can turn several mundane objects into one good one.
Make people tightwads: Don't just give the hero stuff. This is one area where Sorcery! got it right. You didn't even start with the spell components for you spells. Not even easy stuff like sand and pebbles. Now that's mean.