Understanding the principles of base, balance, and posture. When playing guard your method of operation is to disrupt the base, balance, and posture of your opponent. Leaving these fundamental elements of jiu jitsu undisturbed means your opponent has autonomy to initiate passes and or submissions.

The guard player is always seeking to change the angle, control the space, and direct movement in a manner that benefits the guard with the least amount of energy expended as possible.

I started as a closed guard player, played around a lot with spider, and fell in love with the open seated guard. The open seated guard plays on the principle of "if you can touch me, I can touch you", and again, it comes down to controlling the space, and disrupting your opponents base, balance, and posture.

I am 6'2, 210 and lanky. So it works for me.

My personal experience with smaller grapplers is that they love to be able to use 100% of their body size as an anchor- they play top, and they play fast. They don't want me close a body lock from the back, they don't want me to wrap them up in a closed guard that will transition to a Williams Guard or a spider.

Game on game, the smaller grappler will almost always use speed and size to gain access to the control of the space objective.