As I've said in numerous threads: There is no such thing as "metagaming" (at least not until you invent it, claim to want to avoid it, and by doing so make it mandatory for everyone to do it).
Metagaming: using the knowledge of the player to determine what decisions the character makes.Saying it doesn't make it true, though. Metagaming exists all by its lonesome and all we're doing is identifying it. Doing so doesn't make it mandatory to do, either. That's just bupkis.
Metagaming: using the knowledge of the player to determine what decisions the character makes.
Avoiding metagaming, step by step process:
1) Determine what the player knows... and in doing so, metagame.
2) Force the player that knows what is a good idea to jump through hoops like die rolls for knowledge checks or do something they know isn't a good idea - even though a player that had no clue and was guessing is allowed to play their character as making a guess, thus proving it was the player's knowledge - not the character's - that was used to decide the course of action.
You can call it "bupkis" but I have proven it as being true, including that if I recall correctly you and I actually had a conversation on another forum about how I'm not allowed to have my character guess about something in one of your games because I know as a player that the character's guess is correct.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.