Simple - come up with 1 (or more if you wish) held items, and discuss their competitive and/or in game value.
Power Stone
Effect: Boosts Attack and Special Attack by 1 stage; lowers Defence and Special Defence by 1 stage
Use: Ideal for frail attackers.
Guard Stone
Effect: Boosts Defence and Special Defence by 1 stage; lowers Attack and Special Attack by 1 stage
Use: Ideal for weak walls.
Boost Gem
Effect: The next stat change(s) is doubled. If a move affects multiple stats, all stat boosts/penalties will be doubled. Consumed after use
Use: Great for Unburden sweepers, however there is the risk of Intimidate and Sticky Web
Power Stone
Effect: Boosts Attack and Special Attack by 1 stage; lowers Defence and Special Defence by 1 stage
Use: Ideal for frail attackers.
Guard Stone
Effect: Boosts Defence and Special Defence by 1 stage; lowers Attack and Special Attack by 1 stage
Use: Ideal for weak walls.
Boost Gem
Effect: The next stat change(s) is doubled. If a move affects multiple stats, all stat boosts/penalties will be doubled. Consumed after use
Use: Great for Unburden sweepers, however there is the risk of Intimidate and Sticky Web