>>30438725Start with a Pokemon or two that you really like and build around it. In your case, maybe take Togekiss and bring in other members to cover its weaknesses, and then bring in more members to cover theirs.
Make sure you can hit every single typing for Super Effective damage.
Make sure that you have a defensive answer to every type of attack. Is Ground dangerous to your team? Bring in Flying/Levitate so your opponent has to think twice about spamming Earthquake.
Make sure your weakness overlap is minimum. Don't let half your team be weak to rock!
Make sure you have an answer to common dangerous situations. What will you do when something sets up buffs on you? What will you do when there's a stallfag with Toxic and Recover?
Have varied roles and movesets. Have support, have physical offense, physical defense, special offense, special defense. Don't underestimate support and status.
Held items make or break entire sets. Don't underestimate their great importance.
There's a whole lot to keep in mind and consider but that's the gist of it.
