Of course, there’s more to a team than just choosing team members.  Each pokemon on the team has not only its move selections but also its Effort Point distribution to affect its contribution to the team.  Keeping in mind what each pokemon on your team is trained for can help you decide how to train the others.

For instance, if four of your team members have strong Special Defense values, then you probably don’t need to worry about the Special Defense of the last third of your team.  If the team member with Baton Pass and Substitute has a high HP value, you can afford a certain amount of investing in the Defense or Special Defense of your other team members instead of their HP- because that will make the passed Substitutes that much more durable.

By the same rote, you may need to use this to cover what other team members are doing.  If a lot of your team invites physical attacks, then pumping up the physical defense of your tank or wall will leave them in a good position to switch in against something that’s punching their teammates into the floor.

Consider the attack as well.  If you have a pokemon on your team who could either attack physically or specially and you want to know where to invest your training- consider their teammates.  Chances are most of the rest of the team will be pokemon who are heavily biased towards Attack or who bear a strong tendency towards Special Attack.  If one of those two is more prevalent- then invest in the other for your option-laden teammate.  If the two are roughly even, then this would be a good pokemon to make into a mixed attacker, with training and attack moves for both offense stats.

Moves work similarly- if Electric attacks are common, you may need to worry about Ground, Grass, and Electric pokemon coming after you- make sure you’ve got moves floating around your team for that.  If status effects are your bread and butter, you need something you can do about Magic Guard Clefable or things that walk into combat holding Flame Orbs and Toxic Orbs.  If you’re lacking in alternate damage methods, you need to make sure you have a Leech Seed or something on hand for when your opponent throws a well-prepared wall in your way.

This is a form of cross-coverage- but it’s one that all teams need to have to some degree.  Otherwise you run the risk of having a single strategy or pokemon out there that can simply waltz into battle with your team and dance all over their heads until the Miltank come home.  You can’t be absolutely prepared to cover every situation- but you can make sure that there are no glaring holes in what your team is prepared to handle.

Keeping this in mind is key to team-building.