Some one made a thread like this a few years ago, and it really changed my perspective on team building (for the instance that you would actually be in the Pokémon world). I haven't seen any since, so I thought I'd make one (I apologize if any others were created in the past few months).

Basically, you want to build a team that is geared towards survival, in the sense that each member has a specific skill that makes them vital.

For example:

Gengar: Toxic Environment traversal/scout without borders
Magnezone: Electricity Generation/short range transport
Houndoom: Fire producer/smokescreen getaway/hunter
Wailren: Water traversal
Lucario: General combat/healing
Golurk: Heavy lifting/excavation

So it isn't much different than how you would normally make a real team, but the idea is just geared towards survival in more harsh environments and less on battling.