Size
Ideal size is one of the things that vary from position to position. At the tackle positions, generally you are looking for a guy in the 6-4 to 6-7 range around the 300-to-325 pound mark, preferably with long arms to lock onto defenders. When it comes to guards, you’re looking for basically the same thing, although shorter players with a lower center of gravity and more body mass can be a better fit for the position.
Because of the value of a center who can get to the second level in the NFL, mobility is an important asset, so generally, the elite ones are smaller than their counterparts at guard and tackle. Of course, the ideal size of a lineman can also vary from team to team depending on the type of blocking schemes used. Some teams rely on smaller, quicker players in zone blocking schemes while others prefer bigger linemen in more of a power-blocking game.